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QUESTIONS FOR QUESTION BANK SUB-PHYSICS(XII)

DAV PUBLIC SCHOOL ZONE II UNIT-I (Electrostatics) SECTION-A (ONE MARK)

1. How does the Coulomb force between two point charges depend on the electric constant of the intervening medium? 2. An electrostatic field line cannot be discontinuous, why? 3. What does q1+q2=0 signify in electrostatics?

4. What is the electrostatic potential due to an electric dipole at an equatorial point? Is their a electric field? 5. A point charge +Q is placed in the vicinity of a conducting surface. Draw the field lines between the charge and the conducting surface. 6. Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two? 7. Two charges of magnitudes -2Q and + Q are located at point (a, 0) and (4a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘3a’ with its centre at the origin? 8. Why must electrostatic field at the surface of a charged conductor be normal to the surface at every point? Give reason. 9. Why is the potential inside a hollow spherical charged conductor constant and has the same value as on its surface? 10. Figure shows a point charge +Q, located at a distance R/2 from the centre of a spherical metal shell. Draw the electric field lines for the given system. Q.11 why can one ignore quantization of charge when dealing with macroscopic charges?

12 what orientation of an electric dipole in a uniform electric field corresponds to stable equilibrium?

Q13 Name the physical quantity whose SI unit is JC-1

.Is it a scalar or a vector quantity?

Q14 what is the amount of work done in moving 100 µC charge between two points 5 cm apart on an equipotential

surface?

Q15 The distance of the field point on the axis of a small electric dipole is doubled. By what factor will the electric field

due to the dipole change?

16 In a parallel plate capacitor of d =1m the potential difference of 102 V is maintained between the plates. What will be

electric field at points A and B.?

++++++++++++++++++++++

. A

. B

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Q17.A Gaussian surface encloses an electric dipole within it. What is the total flux across sphere?

18Why do the equipotential surfaces do not intersect to each other?

19 Define dielectric constant of a medium. What is its unit?

20A proton is placed in a uniform electric field directed along the positive x- axis. In which direction will it tends to

move?

20 What is the work done in moving a test charge q through a distance 1cm along the equatorial axis of an electric

dipole?

21 Define the term electric dipole moment of dipole. State its S.I unit?

22 Three point charges +2q, -q and + 3q are enclosed within a surface S .What is the electric flux due to this

configuration?

23 Why the electric field inside a dielectric decreases when it is placed in an external electric field?

24 A hollow metal sphere of radius 5 cm is charged such that the potential on it surface is 10V. What is the

potential at the center of the sphere?

25 A metal plate is introduced between the plates of a charged parallel plate capacitor. What its effect on the

capacitance of the capacitor?

26 How does the Coulomb force between two point charges depend upon the dielectric constant of the intervening

medium?

27 Show graphically the variation of charge q with time t when a condenser is charged.

28 Name the physical quantity whose SI unit is JC-1

.Is it a scalar or a vector quantity?

29 If the radius of the Gaussian surface enclosing a charge is halved, how does the electric flux through the

Gaussian surface change?

30 Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal

length. What would be the effect on the force when a plastic sheet is inserted between the two?

31 What is an electro static potential due to an electric dipole at an equatorial point?

32 An electrostatic field line cannot be discontinuous, why?

33 An electric dipole is held in uniform electric field. (i) Show that the net force acting on it is zero

34 The dipole is aligned parallel to the field .Find the work in rotating it through the angle of 180 degree.

35 In which orientation, a dipole placed in a uniform electric field is in (i) stable, (ii) unstable equilibrium

36 Why do the equipotential surfaces due to uniform electric field not intersect to each other?

37 Define dielectric constant of a medium. What is its unit?

38 A proton is placed in a uniform electric field directed along the positive x- axis. In which direction will tend to

move

39 What is the work done in moving a test charge q through a distance 1cm along the equatorial axis of an electric

dipole?

40 Define the term electric dipole moment of dipole. State its S.I unit.

41 Why do the equipotential surfaces due to uniform electric field not intersect to each other?

42 Define dielectric constant of a medium. What is its unit

43 A proton is placed in a uniform electric field directed along the positive x- axis. In which direction will tend to

move?

SECTION-B (TWO MARKS) 1. A parallel plate capacitor of capacitance C is charged to a potential V. It is then connected to another uncharged capacitor having the same capacitance. Find out the ratio of the energy stored in the combined system to that stored initially in the single capacitor. 2. Figure shows the field lines on a positive charge. Is the work done by the field in moving a small positive charge from Q to P positive or negative? Give reason. 3. Two uniformly large parallel thin plates having charge densities +ρand –ρ are kept in the X-Z

plane at a distance ‘d’ apart. Sketch an equipotential surface due to electric field between the plates. If a particle of mass m and charge ‘–q’ remains stationary between the plates, what is the magnitude and direction of this field? 4. A slab of material of dielectric constant K has the same area as that of the plates of a parallel plate capacitor but has the thickness d/2, where d is the separation between the plates. Find out the expression for its capacitance when the slab is inserted between the plates of the capacitor. 5. A point charge Q is placed at point O as shown in the figure. What is the sign of the potential difference VA – VB if Q is

(i) positive (ii) negative?

Q6 A charged particle is free to move in an electric field. Will it always move along an electric line of force?

Q7. If V (=q/4πεor) is the potential at a distance r due to a point charge q, then determine the electric field due to a

point charge q, at a distance r.

Q.8 Draw an arrangement of three point charges separated by finite distances, that has zero electric Potential energy.

Q9 Charge of 2C is placed at the centre of a cube of volume 8 cm3. What is the electric flux passing through one face?

10 Three charges, each equal to +2C are placed at the corners of an equilateral triangle. If the force between any

two charges be F, then what will be the net force on either Charge?

Q11 A charged particle q is shot towards another charged particle Q which is fixed, with a speed v. It approaches Q

up to a closest distance r and then returns. If q were given a speed 2v,then find the closest distance of approach.

11 Two capacitors of capacitance 6mF and 12mF are connected in series with the battery .The voltage across the

6mF capacitor is 2 volt .Compute the total battery voltage.

12 Five identical capacitors, each of capacitance 1mF are connected between points X and Y . If the equivalent

capacitance of the combination between X and Y is 3mF. Make the possible arrangement.

13 . An electric dipole is held in uniform electric field. (i) Show that the net force acting on it is zero

14 The dipole is aligned parallel to the field .Find the work in rotating it through the angle of 180 degree.

15 . Deduce the expression for the energy stored in a parallel plate capacitor C having charges +Q and -Q on its

plate.

16 . Two uniformly large parallel thin plates having charge densities +ρ and -ρ are kept in X-Z plane at a distance d

apart .Sketch an equipotential surface due to electric field between the plates .If particle of mass m and charge

-q remain stationary between the plates . What is the magnitude and direction of this field?

17 . Derive an expression for the electric potential at any point along the axial line of an electric dipole?

18 A spherical Gaussian surface encloses a charge of 8.85 x10 -10

C (i) Calculate the electric flux passing through

the surface (ii) How would the flux change if the radius of the Gaussian surface is doubled and why?

19 A cubical Gaussian surface encloses a charge of 8.85 x 10 -1o

C in vacuum at the center. Calculate the electric

flux passing through one of its faces?

20 Draw three equipotential surfaces corresponding to the field that uniformly increases in magnitude but remain

constant along -z direction. How is the surface different from that of a constant electric field along the Z-

direction?

21 .Prove that a closed equipotential surface with no charge within itself must enclose an equipotential volume.

22 Two fixed point charges +4e and +e units are separated by a distance "a" .Where should the third point charge

be placed for it to be in equilibrium?

23 Let two conducting spheres of radii r1 and r2 be joined by thin wire and total charge q be given to them .Prove

that the charges on the spheres will be in the ratio of their radii.

24 A 4µF capacitor is charged by a 200V supply. The supply is then disconnected and the charged capacitor is

connected to another uncharged 2µF capacitor. How much electrostatic energy of the first capacitor is lost in

the process of attaining the steady situation?

25 .The electric field in a region is radially outward and varies with distance r as E=250 r Vm-1

.Calculate the charge

contained in a sphere of radius 0.2 m centered at the origin.

26 .How charge given to inner sphere transfers to outer sphere?

27 State gauss’s theorem. Use it to find electric field due infinite line of charge. What is the effect on electric field,

when charge density gets double and distance between point and line of charge is half.

28 There is an isolated parallel plate capacitor of capacitance C charged to a potential difference V. If the

separation between the plates is doubled, how the following quantities will vary:

(i) Capacitance

(ii)Potential difference

(iii) Charge on the capacitor

(iv) Electric field inside the plates

(v) Energy stored.

29 What is an electric field? Find an expression for electric field along the axial line of electric field. Give its SI unit.

30 What is an electric polarization of a dielectric? What is the effect on capacitance of a capacitor when a dielectric

of width ‘t’ is placed between the two plates of parallel plate capacitor?

31 Find effective capacitance of given network.

SECTION-C (THREE MARKS) 1.A spherical Gaussian surface encloses a charge of 8.85x10 -8 C. (i) Calculate the electric flux passing through the surface (ii) If the radius of the Gaussian surface is doubled, how would the flux change? 2. Show that an electric dipole kept in uniform electric field does not experience force but experiences a torque. Deduce an expression for torque. Draw electric lines force for an electric dipole. 3. A parallel plate capacitor is charged by a battery. After some time the battery is disconnected and a dielectric slab of dielectric constant K is inserted between the plates. How would (i) the capacitance, (ii) the electric field between the plates and (iii) the energy stored in the capacitor, be affected? Justify your answer.

4. A test charge is q moved without acceleration from A to C along the path from A to B then B to C in electric field E as shown in the figure. (i) Calculate the potential difference between A and C (ii) at which point of two potential difference is more& why? 5. What is a Electric Dipole ? Find electric field due to a dipole along axial line at a distance r from the centre of dipole. 6.State Gauss’s law in electrostatic. A cube with each side ‘a’ is kept in an electric field given by E =C x i (as is shown in the figure) where C is a positive dimensional constant. Find out the electric flux through the cube.

7.Two point charges +10µC and –10 (i) Calculate the electrostatic potentia potential energy to be at infinit (ii) Draw an equipotential surfac (iii) How much work is required to 8.In a parallel plate capacitor with air between the plates, each plate has an area of 6 the separation between the plates (i) Calculate the capacitance of the capacitor. (ii) If this capacitor is connected to 100 V supply, what would be the charge on each plate? (iii) How would charge on the plates be affected, if a 3 mm thick mica sheet of between the plates while the voltage supply remains connected? 9A capacitor of 200 pF is charged by a 300V battery. The battery is then disconnected and the charged

capacitor is connected to another uncharged capacitor of 100 pF.

energy stored in the final energy stored in the combined system and the initial energy stored in the initial

kinetic energy stored in single capacitor,

10 Define term electric dipole moment is it a scalar or vector?

at a point on the equipotential plane of an electric dipole of length 2a.

11Two point charge 3 micro coulomb and

Calculate the electric field at the mi

experienced by negative test charge of magnitude 1.5 x 10

placed at this point.

12A point charge (+Q) is kept in the vicinity of uncharged

conducting plate. Sketch electric field lines between the charge

and the plate. Two infinitely large plane thin parallel sheets having

surface charge densities Ϭ1 and Ϭ

figure. Write the magnitudes and directi

regions marked II and III.

13 Two parallel plate capacitors X and Y, have the same area of plates and same separation

between them. X has air between the plates while Y contains a dielectric medium of є

a. Calculate capacitance of each capacitor if

b. Calculate the potential difference between the plates of X and Y.

c. What is the ratio of electrostatic energy stored in X and Y?

14 Two similarly and equally charged identical metal spheres A and B repel eac

of 2x10-5

N. A third identical uncharged sphere C is touched with A and then placed at the midpoint

between A and B. Calculate the net electric force on C .

15 Obtain the equivalent capacitance of the network in adjoining

figure. For a 300V supply, determine the charge and voltage across

each capacitor.

16 Derive an expression for the torque on an electric dipole in a uniform electric field.

17 Derive an expression for the effective capacitance when capacitors are connected in

(a) series and (b) parallel

18 Explain the principle of a capacitor and derive an expression for the capacitance of a parallel plate

capacitor.

10µC are separated by a distance of 40 cm in airpotential energy of the system, assuming the zero infinity. surface of the system.

o separate the two charges infinitely away from .In a parallel plate capacitor with air between the plates, each plate has an area of 6

separation between the plates is 3 mm. ) Calculate the capacitance of the capacitor. ) If this capacitor is connected to 100 V supply, what would be the charge on each plate?) How would charge on the plates be affected, if a 3 mm thick mica sheet of between the plates while the voltage supply remains connected?

capacitor of 200 pF is charged by a 300V battery. The battery is then disconnected and the charged

capacitor is connected to another uncharged capacitor of 100 pF. Calculate the difference between the final


kinetic energy stored in single capacitor,

Define term electric dipole moment is it a scalar or vector? Deduce an expression for the electric field

at a point on the equipotential plane of an electric dipole of length 2a.

Two point charge 3 micro coulomb and -3 micro coulomb are located 20cm a part in vacuum (i)

Calculate the electric field at the midpoint O of the line AB joining two charges (ii) What is the force

experienced by negative test charge of magnitude 1.5 x 10-9

C

A point charge (+Q) is kept in the vicinity of uncharged

ectric field lines between the charge

and the plate. Two infinitely large plane thin parallel sheets having

Ϭ2 (Ϭ1 >Ϭ2 ) are shown in the

figure. Write the magnitudes and directions of the net fields in the

Two parallel plate capacitors X and Y, have the same area of plates and same separation

between them. X has air between the plates while Y contains a dielectric medium of є

Calculate capacitance of each capacitor if equivalent capacitance of the combination is 4 mF.

Calculate the potential difference between the plates of X and Y.

What is the ratio of electrostatic energy stored in X and Y?

Two similarly and equally charged identical metal spheres A and B repel each other with a force


between A and B. Calculate the net electric force on C .

Obtain the equivalent capacitance of the network in adjoining

figure. For a 300V supply, determine the charge and voltage across

Derive an expression for the torque on an electric dipole in a uniform electric field.

on for the effective capacitance when capacitors are connected in

Explain the principle of a capacitor and derive an expression for the capacitance of a parallel plate

C are separated by a distance of 40 cm in air- o of the

m each other .In a parallel plate capacitor with air between the plates, each plate has an area of 6 x 10-3 m2 and

) If this capacitor is connected to 100 V supply, what would be the charge on each plate? ) How would charge on the plates be affected, if a 3 mm thick mica sheet of K = 6 is inserted

capacitor of 200 pF is charged by a 300V battery. The battery is then disconnected and the charged

Calculate the difference between the final


Deduce an expression for the electric field

3 micro coulomb are located 20cm a part in vacuum (i)

dpoint O of the line AB joining two charges (ii) What is the force

Two parallel plate capacitors X and Y, have the same area of plates and same separation

between them. X has air between the plates while Y contains a dielectric medium of єr = 4.

equivalent capacitance of the combination is 4 mF.

h other with a force


Derive an expression for the torque on an electric dipole in a uniform electric field.

on for the effective capacitance when capacitors are connected in

Explain the principle of a capacitor and derive an expression for the capacitance of a parallel plate

19 State Coulomb's law and express it in vector form. Derive it using Gauss theorem.

20 A parallel plate capacitor is changed to a potential difference , ‘V’ by a dc source. The capacitor is then

disconnected from the source. If the distance between the plates is doubled. State with reason how

the following will change : electric field between the plates, capacitance and energy stored in the

capacitor.

21 A test charge ‘q’ is moved without acceleration from A to C

along the path from A to B, then from B to C in electric field E

as shown in the figure.

(i) Calculate the potential difference between A and C.

(ii) At which point (of the two) is the electric potential more and why?

22 A hollow cylindrical box of length 1 m and area of cross-

section 25 cm2 is placed in a three dimensional coordinate

system as shown in the figure. The electric field in the

region is given by E = 50 x ,

where E is in NC–1

and x is in meters. Find

(i) Net flux through the cylinder.

(ii) Charge enclosed by the cylinder.

23.A 4μF capacitor is charged by a 100V supply. The supply is then disconnected and the charged

capacitor is connected to another uncharged 2μF capacitor. What is common potential .How much

electrostatic energy of the first capacitor is lost in the process of attaining the steady situation

24Q24 A capacitor of 200 pF is charged by a 300V battery. The battery is then disconnected and the charged

capacitor is connected to another uncharged capacitor of 100 pF. Calculate the difference between the final energy

stored in the final energy stored in the combined system and the initial energy stored in the initial kinetic energy stored

in single capacitor,

Q25.Define term electric dipole moment is it a scalar or vector? Deduce an expression for the electric field at a point on

the equipotential plane of an electric dipole of length 2a.

Q26 Two point charge 3 micro coulomb and -3 micro coulomb are located 20cm a part in vacuum (i) Calculate the

electric field at the midpoint O of the line AB joining two charges (ii) What is the force experienced by negative test

charge of magnitude 1.5 x 10-9 C placed at this point.

Q27. A capacitor has some dielectric between its plates, and the capacitor is connected to a DC source. The battery is

now disconnected and the dielectric removed , State whether the capacitance the energy stored in it electric field ,

chage stored and the voltage will increased , decrease or remain constant.

SECTION-E (FIVE MARKS)

1.Derive an expression for the energy stored in a parallel plate capacitor. On charging a parallel plate capacitor to a potential V, the spacing between the plates is halved and a dielectric medium of Єr = 10 is introduced between the plates, without disconnecting the d.c. source. Explain using suitable expressions, how the (i) capacitance, (ii) electric field and (iii)energy density of the capacitor changes. 2. (a)State and prove Gauss Theorem. Use it to find electric field due to a sheet of charge having charge density density σ. (b) Two infinitely large plane thin parallel sheets having surface charge densities σ1 and σ2 (σ1 >σ2 ) are shown in the figure. Write the magnitudes and

directions of the net fields in the regions marked II and III. 3. Using Gauss’ law deduce the expression for the electric field due to a uniformly charged spherical conducting shell of radius R at a point (i) outside and (ii) inside the shell. Plot a graph showing variation of electric field as a function of r > R and r < R.(r being the distance from the centre of the shell) 4 Given two parallel conducting plates of area A and charge densities + σ & -σ. A dielectric slab of constant K and a conducting slab of thickness d each are inserted in between them as shown. (i) Find the potential difference between the plates. (ii) Plot E versus x graph, taking x=0 at positive plate and x=5d at negative plate. 5.(a) Two isolated metal spheres A and B have radii R and 2R respectively, and same charge q. Find which of the two spheres have greater : (i) Capacitance and (ii) energy density just outside the surface of the spheres. (b) (i) Show that the equipotential surfaces are closed together in the regions of strong field and far apart in the regions of weak field. Draw equipotential surfaces for an electric dipole. (ii) Concentric equipotential surfaces due to a charged body placed at the centre are shown. Identify the polarity of the charge and draw the electric field lines due to it.

6 Define electric flux. Write its S.I units .Using Gauss’s, Prove that the electric field at a point due to

uniformly charged infinite plane sheet is independent of distance from it. How is the field directed if (i)

the sheet is positively charged (ii) negatively charged.

7 What is dielectric? Why does the capacitance of a parallel plate capacitor increase on introduction of a

dielectric in between its two plates ?Derive an expression for the capacitance of such a capacitor

having two identical plates each of area A and separated by a distance x .The space between the plates

medium of dielectric constant k.

8 State Gauss Theorem. Use it to find electric field due to (a) A metallic sphere of charge having charge

density ρ. (i) outside (ii) on the surface (iii) inside.

9 Two capacitors with capacitance C1 and C2 are charged to a potential V1 and V2 respectively and then

connected in parallel.

Calculate (i) Common potential across the combination (ii) The charge in each capacitor (iii)The

electrostatic energy stored in the system (ii) Amount of heat energy produced

UNIT –II CURRENT ELECTRICITY

SECTION-A (ONE MARK)

1. Plot a graph showing variation of temp – resistivity of a semiconductor. 2. Why resistance become more in series combination ? 3. Under what condition maximum current can be drawn from a cell? 4. When we switch on an electric bulb, it lights up almost instantaneously though drift velocity of electrons in copper wires is very small, Give reasons? 5. If a p.d ‘v’ is applied across a conductor is increased to 2v, how will the drift velocity of the electrons change? 6. Give an example of a material each for which temperature coefficient of resistivity is (i) positive, (ii) negative.

7 Define resistivity of a conductor. Write its S. I unit.

8 A steady current flows in a metallic conductor of non-uniform cross-section .Which of these quantities

is constant along the conductor , current , current density, Drift speed, Electric field?

9 Sketch the graph showing variation of resistivity of carbon with temperature.

10 Two wires of equal length, one of copper and the other of manganin have the same resistance. Which

wire is thicker?

11 Why resistance becomes less in parallel combination?

12 How can we increase the sensitivity of a potentiometer?

13 Under what conditions the terminal potential difference of a cell be greater than its e.m.f.

14 Why Wheatstone bridge method is considered unsuitable for the measurement of a very high

resistance?

15 How does drift velocity of electrons in a metallic conductor vary with the rise in

temperature?

16 Show the variation of resistivity of Si with temperature in a graph.

17 The graph shown in the figure represents a plot of current versus

voltage for a given semiconductor. Identify the region, if any, over

which the semiconductor has a negative resistance.

18 The V-I graph of two metallic conductor of same material

and same thickness with different length are as shown.

Which is of greater length?

.20 .What happens to the drift velocity Vd of electron and to the resistance R, if the length of the conductor is

doubled ( keeping potential difference unchanged ).

21.Under what condition maximum current can be drawn from a cell?

22Define resistivity of a conductor. Write its S. I unit.

23. A steady current flows in a metallic conductor of non-uniform cross-section .Which of these quantities is

constant along the conductor , current , current density, Drift speed, Electric field?

Q24 Sketch the graph showing variation of resistivity of carbon with temperature.

Q25 Two wires of equal length, one of copper and the other of manganin have the same resistance. Which wire is

thicker?

Q26. How can we increase the sensitivity of a potentiometer?

Q28 Under what condition will the terminal potential difference of a cell be greater than itself?

SECTION-B (TWO MARKS) 1. The V – I graph for a metallic wire at two different temperatures T1 and T2 is shown in the figure. Which of the two temperatures is higher and why ?

2. Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0 ×10–7 m2 carrying a current of 1.5 A. Assume the density of conduction electrons 8.5 × 1028 m–3. 3.In a meter bridge balance point is found at a distance l1 with resistances R and S as shown in figure. When an unknown resistance X is connected in parallel with resistance S, the balance point shifts to a distance l2. Find the expression for X in terms of l1, l2 and S. 5 .Define relaxation time of the free electrons drifting in a conductor .How is it related to the drift velocity of free electrons? Use this relation to deduce the expression for the electrical

T1

T2

I

V

resistivity of the material. 6. Using the mathematical expression for the conductivity of material, explain how it is varies with temperature for

(i) semiconductor (ii) good conductors,

7. Two metallic wires of the same material have the same length but cross -sectional area is in the ratio 1:2 ,They

are connected (i) in series and (ii) in parallel , compare the drift velocity of electrons in the two wires in both

the cases .

8. Derive an expression for drift velocity of free electrons in a conductor in terms of relaxation time.

9. Define ionic mobility. Write its relationship with relaxation time. How does one understand the temperature

dependence of resistivity of a semiconductor?

10. Explain how electron mobility changes for a good conductor when ; (i) the temperature of the conductor is

decreased at constant potential difference and (ii) applied potential difference is doubled at constant

temperature

11Establish a relation between current and drift velocity.

12A storage battery of emf 12V and internal resistance of .5 ohm is to be charged by a 120 v d.c supply of negligible

resistance. What resistance is required in the circuit for the charging current to be 3A? What is the terminal voltage

of the battery during charging?

13. Define the term Resistivity of a conductor, give its SI Unit. Show that the resistance R of a conductor is given by

ml/ne2τA where symbols has their usual meanings.

14. A conductor of length l is connected to a DC source of potential V. If the length of the conductor is triple by

stretching it keeping V constant, explain how the following factors vary in the conductor (i) Drift speed of

electron (ii) resistance.

15. State underlying principle of potentiometer. Describe briefly, giving the necessary circuit diagram, how a

potentiometer is used to measure the internal resistance of a given cell.

16. A potential difference of V volts is applied to a conductor of length L and diameter D. How will the drift velocity

of electrons and the resistance of the conductor change when (:i.) V is double (ii.) L is halved an iii. D is

halved, where, in each case, the other factors remain same. Give reason in each case.

17 Draw V ~ I graph for Ohmic and non-ohmic materials. Give one examples

of each.

18Two students ‘X’ and ‘Y’ perform an experiment on potentiometer

separately using the circuit given. Keeping other parameters

unchanged, how will the position of the null point be affected it

(i) ‘X’ increases the value of resistance R in the set-up by keeping the key

K1 closed and the K2 open?

(ii) ‘Y’ decreases the value of resistance S in the set-up, while the key K2 remain open and the key K1

closed?Justify.

19 Wheatstone bridge method is considered unsuitable for the Measurement of very small resistances. Why?

20 First a set a n equal resistors of R each are connected in Series to a battery of emf E and internal resistance R.

A Current I is observed to flow. Then the n resistors are connected in parallel to the same battery.

It is observed that the current is increased 10 times. What is ‘n’ ?

21.The plot of the variation of potential difference across a combination of three

identical cells in series, versus current is as shown below. What is the emf of each

cell ?

21 A wire has resistance of 10 Ω. It is drawn to increase its length by three times.

What is new resistance?

22 Two wires one of managing and other is copper have equal length and equal resistance .Which one of these

wires will be thicker?

23 State the principle of working of a potentiometer. Define Potential gradient and write its SI unit.

24 In a meter bridge , the null point is found to be at a distance of 40 cm from A. if a resistance of 12Ω is

connected in parallel with S then balancing point shifted to 50 cm. Find the value of R.

25 Define resistivity of the conductor. Plot a graph showing the variation of resistivity with temperature for a

metallic conductor.

26 You are given 8 Ω resistor. What length of wire of resistance 120 Ωm-1

should be joined in parallel with it to get a

value of 6 Ω ?

27. Three resistance 3Ω,6Ω and 9Ω are connected to a battery. In which of them will the power dissipation be maximum

if

a) They all are connected in parallel

b) They all are connected in series Give reason.

28. A silver wire has a resistance of 2.1Ω at 27.5˚c and a resistance of 2.7Ω at 100˚c. Determine the temperature coeff.

of resistivity of silver.

29. The variation of potential difference with length in case of two potentiometers A and B is given below .Which of the

two is more sensitive.

30. If the length of the wire conductor is doubled by stretching it , keeping potential difference constant by what factor

the drift speed of the electron changes.

31. Two 120V light bulbs , one of 25W and another of 200W are connected in series . One bulb burnt out almost

instantaneously ?.Which one was burnt and why?.

32. A cylindrical metallic wire is stretched to increase its length by 5% . Calculate the Percentage change in resistances.

33. A wire of resistance 4R is bend in the form of circle .What is the effective resistance between the ends of diameter?.

34. Two wires A and B have same lengths and same material, have their cross sectional areas 1:4 , what would be the

ratio of heat produced in these wires when the voltage across each is constant.

35. Two bulbs whose resistance are in the ratio of 1:2 are connected in parallel to a source of constant voltage. What

will be the ratio of power dissipation in these?

36. Plot of current I versus time interval is given below. Find the charge that flows through the wire during this time

period

SECTION-C (THREE MARKS

1. Define resistivity of the conductor. Plot a graph showing the variation of resistivity with temperature for a metallic conductor. Explain the behavior using mathematical expression.

2. A storage battery of e.m.f. 8V and internal resistance 0.5Ω is being charged by a 120V D.C supply using a resistor of 15.5Ω. What is the terminal voltage of the battery during charging. 3. State the principle of working of a potentiometer . Draw a circuit diagram and derive an

expression to compare the emf of two primary cells by using a potentiometer .

4. Two wires X and Y have the same resistivity but their cross-sectional areas are in the ratio 2:3 and lengths in the ratio 1:2 . They are first connected in series and then in parallel to a DC

source. Find the ratio of drift speeds of electrons in the two wires for the two cases. 5. Figure shows two circuits each having a galvanometer and a battery of 3V.When the galvanometers in each arrangement do not show any deflection, obtain the ratio R1/R2 6. A cell, with a finite internal resistances r is connected across the two external resistances R1and R2(R1>R2) one by one .In which case would the terminal potential difference of the cell be more? Justify your answer. . 7. Derive the expression for effective emf of two cells of different emf connected in parallel? 8. For the circuit shown here, would the balancing length increase, decrease or remain the same, if

(i)R1 is increased

(ii) R2 is decreased

Without any other change, (in each case) in the rest of the circuit.

Justify your answers in each case.

9. The figure shows experimental set up of a meter bridge. When the two unknown resistances X and Y are inserted, the null point D is obtained 40 cm from the end A. When a resistance of 10 Ω is connected in series with X, the null point shifts by 10 cm. Find the position of the null point when the 10 Ω resistance is instead connected in series with resistance ‘Y’. Determine the values of the resistances X and Y. 10. (a) The electron drift arises due to the force experienced by electrons in the electric field inside the conductor. But force should cause acceleration. Why then do the electrons acquire a steady average drift speed? (b) If the electron drift speed is so small, and the electron’s charge is small, how can we still obtain large amounts of current in a conductor? (c) When electrons drift in a metal from lower to higher potential, does it mean that all the ‘free’ electrons of the metal are Moving in the same direction? Explain. 11. A number of identical cells, n, each of emf E, internal resistance r connected in series are charged by a d.c. source of emf E, using a resistor R (i) Draw the circuit arrangement. (ii) Deduce the expressions for (a) the charging current and (b) the potential difference across the combination of the cells. 13. Two cells of E.M.F. 10 V and 2 V and internal resistances 10 Ω and 5 Ω respectively, are connected in parallel as shown. Find the effective voltage across R. 14.The potential difference across a resistor ‘r’ carrying current ‘I’ is Ir. (i) Now if the potential difference across ‘r’ is measured using a voltmeter of resistance ‘Rv’, show that the reading of voltmeter is less than the true value.

(ii) Find the percentage error in measuring the potential difference by a voltmeter. (iii) At what value of Rv, does the voltmeter measures the true potential difference? 15. You are given two sets of potentiometer circuit to measure the emf E1 of a cell. Set A: consists of a potentiometer wire of a material of resistivity ρ1, area of cross-section A1 and length l. Set B: consists of a potentiometer of two composite wires of equal lengths l/2 each, of resistivity ρ1, ρ2 and area of cross-sectionA1, A2 respectively. (i) Find the relation between resistivity of the two wires with respect to their area of cross section, if the current flowing in the two sets is same.

(ii) Compare the balancing length obtained in the two sets. 16 Two heating elements of resistances R1 and R2 when operated at a constant supply of voltage V, consume

powers P1 and P2 respectively. Deduce the expressions for the power of their combination when they are in

turn connected in (i)series and (ii) parallel across the same voltage supply.

17 Prove the current density of a metallic conductor is directly proportional to the drift speed of electrons.

18 A number of identical cells, n each of emf E , Internal resistance r connected in series are charged by d.c source

of emf E' , Using a resistor R . (i) Draw the circuit arrangement (ii) Deduce the expression for (a) the charging

current and (b) the potential difference across the combination of the cells.

19 On what principle does meter bridgework? Draw a circuit diagram and explain how this device can be used for

determination of an unknown resistance?

20 A number of identical cells ,n, each of emf E and internal resistance r connected in series are charged by a d.c.

source of emf E′ using a resistor R i) Draw the circuit arrangement. ii)Deduce the expressions for (a) the

charging current and (b)the potential difference across the combinations of the cells.

21 Define the term current density of a metallic conductor. Deduce the relation connecting current density (J) and

the conductivity of the conductor, when an electric field E , is applied to it .

22 Two conductors are made of the same material and have the same length. Conductor A is solid wire of

diameter 1mm .Conductor B is a hallow tube of outer diameter 2mm and inner diameter 1mm. Find the ratio

of résistance R1 and R2.

23 State and explain the principle of Wheat Stone's principle. Deduce it using Kirchhoff’s laws.

24 Describe how you will determine the resistance of a given wire using Meter Bridge.

25 Explain the principle of a potentiometer. Describe how will you determine the ratio of emf s of two primary cells

using Potentiometer.

26 Explain the variation of resistance and resistivity with temperature

and hence define temperature coefficient of resistance and

resistivity.

27 Derive an expression for conductivity in terms of mobility

28 Explain the colour coding of carbon resistors.

29 Derive an expression for the current in a circuit with external

resistance R when (a) n identical cells of emf E and internal

resistance r are connected in series (b) m identical cells are connected in parallel

30 In a meter bridge, the null point is found at a distance of 60.0 cm from A.

If now a resistance of 5 ohm is connected in series with S, the null point occurs at 50 cm. Determine the values

of R and S.

31 A 10 m long wire of uniform cross-section and 20Ώ resistance is used in a

potentiometer. The wire is connected in series with a battery of 5 V along with an external resistance of

480Ώ. If an unknown EMF E is

balanced at 6.0 m length of the wire, calculate (i) potential gradient of the potentiometer (ii) Unknown emf E

32 Explain giving reasons how the internal resistance of a cell Changes in the following cases :

(a) When concentration of the electrolyte is increased

(b) When area of the anode is decreased

(c) When temperature of the electrolyte is increased

33 For the potentiometer circuit shown in the given figure, points X and Y represent the two terminals of an

unknown emf E'. A student observed that when the jockey in moved from the end A to the end B of the

potentiometer wire, the deflection in the galvanometer remains in the same direction. What may be the two

possible faults in the circuit that could result in this observation? If the galvanometer deflection at the end B is

(i) more, (ii) less, than that at the end A, which of the two faults, listed above, would

be there in the circuit ?Give reasons in support of your answer in each case.

34 A potentiometer of 10 meter long having resistance of 2 ohm/m is connected to a cell of 3V with

a resister of 30 ohm in series..Find potential gradient. If a cell of 1.5 V is used to compare find the position of

balancing point.

35 A cell, of emf 4V and internal resistance of. 5 ohm is connected across of a

load of resistances i) 7.7 ohm ii) 11.5ohm. Calculate the ratio of the

difference in the emf of the cell and the potential drop across the load, and

the ratio of the current in the two cases.

36 State and explain Kirchhoff’s laws. Using Kirchhoff’s rules determine the

value of unknown resistance R in the circuit so that no current flows

through 4ῼ resistance. Also find the potential difference between A and D.

37 A student has two wire of iron and copper of equal length and diameter. He first joins two wires in series and

pass electric current through the combination which increases gradually. After that he joins two wires in parallel and

repeats the process of passing current. Which wire will glow first in each case?

38. Total resistance of the circuit is R/3 in which three identical resistors are connected in parallel. Find the value of each

resistance?.39

39. Amount of charge passing through the cross section of a wire is q(t)=at2+bt+c.Write the dimensional formula for a, b

and c. If the values of a, b and c in SI unit are 6, 4, 2 respectively. Find the value of current at t=6 seconds.

40 Prove that current density of a metallic conductor is directly-proportional to the speed of electrons.

41 Name the carriers of electric current in

1) a bar made of silver

2) hydrogen discharge tube

3) a germanium semiconductor

4) a wire made of alloy nichrome

5) supper conductor.

6) salt water

42 A uniform wire of resistance “R” is shaped into a regular “n” sided polygon, where “n” is even. Find the equivalent resistance between

1) opposite corners of the polygon

2) adjacent corners of the polygon.

43. Under what condition is the heat produced in an electric circuit

1) directly proportional

2) inversely proportional to the resistance of the circuit?

UNIT-III (MAGNETIC EFFECT OF CURRENT AND MAGNETISM) SECTION-A (ONE MARK)

1 What is angel of dip at a place where horizontal and vertical components of earth ,s magnetic

field are equal? 2. The vertical component of earth’s magnetic field at a place i√3 times the horizontal component. What is the value of angle of dip at that place? 3.. A proton is moving along +ve x- axis in the presence of uniform magnetic field along + y- axis. What is the direction of force acting on it. 4. No net magnetic force acts on a closed current loop placed in a uniform magnetic field. Why? 5. An electron does not suffer any deflection while passing through a region of uniform magnetic field. What is the direction of the magnetic field? 6. In a magnetic field, a charge moves normal to the fields; will its speed increase or decrease? 7. An α-particle and a proton moving with the same speed enter the same magnetic field region at right angles to the direction of the field. Find the ratio of the radii of the circular paths which the two particles may describe. 8. A proton moving with a velocity v along +x-axis enters a uniform magnetic field B directed along +y-axis. What is the magnitude and direction of force acting on the proton? 9. In Bohr's model of hydrogen atom, the electron moves around the nucleus in a circular

orbit of radius 5x10–11m. Its time period is 1.5x10–16second. Find current associated with the electron motion. 10. How will the magnetic field intensity at the centre of a circular coil carrying current will Change, if current through the coil is doubled and the radius of the coil is halved? 11. Using the concept of force between two infinitely long parallel current carrying conductors, define one ampere of current. 12. Define one tesla using the expression for the magnetic force acting on a particle of charge ‘q’ moving with velocity v in a magnetic field B. 13How angle of dip changes if we are moving from Australia to England.

14 Write two factors by which voltage sensitivity of a galvanometer can be increased. 15 In hydrogen atom, if the electron is replaced by a particle which is 200 times heavier but has the same charge,

how would its radius change.

16 Under what condition will the force exerted by the magnetic field on a charged particle be (i) maximum (ii)

minimum.

17 What are the advantages of radial magnetic field on a moving coil galvanometer?

18 Write two properties of material used as suspension wire in a moving coil galvanometer?

.

19 Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. Why?

20 Which has greater resistance (i) millimeter or ammeter and (ii) milivoltmeter or voltmeter?

21 In a certain region of space, electric field E and magnetic field B are perpendicular to each other. An electron

enters in the region perpendicular to the directions of both B and E and moves un deflected. Find the velocity

of the electron.

22 What is the angle of dip at a place where the horizontal and vertical components of earth magnetic field are

equal?

23 .Two identical charged particles moving with the same speed enter a region of uniform magnetic field. If one of

these enters normal to the field direction and the other enters along a direction at 300 with the field, what would be the

ratio of their angular frequencies?

23 Where on the surface of Earth is the angle of dip zero?

24 What is angle of Dip at North pole of the Earth.

25 A narrow beam of proton and deuterons has same momentum, enter s the uniform magnetic field

perpendicularly. Find the ratio of radius of circular path described by them.

26 Give two essential characteristics of a material used for preparing an electromagnet.

27 How does angle of dip change as one goes from magnetic pole to magnetic equator of the Earth?

28 Write two factors by which voltage sensitivity of a galvanometer can be increased.

29 In hydrogen atom, if the electron is placed by a particle which is 200 times heavier but has the same charge , how

would its radius change .

30 The pole of a magnet is brought near to a stationary charge. What will be the force experienced by pole?

31 Current ‘I’ flows along the length of an infinitely long straight thin walled pipe. What s the magnetic field at any point

on the axis of pipe?

32 . The Earth’s core contains iron but geologists do not regard this as a source of Magnetic Field, Why?

33 A Magnetic Field dipole placed in a Magnetic Field experiences a net force. What can you say about the Nature of

Magnetic Field?

SECTION-B (TWO MARKS)

1. From molecular view point, discuss the diamagnetism and its temperature dependence of susceptibility. 2. Two straight long parallel conductors carry currents I 1 and I 2 in the same direction. Draw diagram how conductor of current I2 experience force due to magnetic field due to I1 . 3. Two wires of equal length carrying same current are bent into a circle and a square respectively. These are then placed in a uniform magnetic field. Which of them will experience maximum torque and why? 4. A rod l is rotating with a angular velocity ω in a uniform magnetic field B . Derive the potential difference developed at the ends of two rod? 5. Draw magnetic field lines when i) diamagnetic ii)paramagnetic substance is placed in an external magnetic field, which magnetic property distinguishes this behavior of the field lines due to the two substances . 6. An electron beam passes through a region with a velocity v where uniform electric and magnetic field are present. The beam will pass un deflected without any change in its velocity. What can

we say about the (a) Relative direction of E , V and B. (b) Magnitude of E and B. 7. Define the terms magnetic dip and magnetic declination ? 8.. Find the magnetic field at any point on the axis of a circular coil carrying current and hence find the magnetic Field at its centre. 9. What is reduction factor of galvanometer? Write an expression for it.

10 Draw magnetic field lines when a (i) diamagnetic (ii) paramagnetic substance is placed in an external magnetic

field. Which magnetic property distinguishes this behavior of field lines due to the two substances?

.

11 How do you convert a galvanometer into an ammeter? Why an ammeter is always connected in series?

12 A circular coil of closely wound N turns and radius r carries a current I. Write the expression for the following :(i)

the magnetic field at the centre (ii) the magnetic moment of the coil

13 A charge ‘q’ moving along the x-axis with a velocity v is subjected to a uniform magnetic field B along the z-axis as

it crosses the origin O. (i) Trace its trajectory. (ii) Does the charge gain kinetic energy as it enters the magnetic

field? Justify your answer.

14 A circular coil of N turns and diameter "d" carries a current I. It is rewound to make another coil of diameter

"2d”, current I remaining the same. Calculate the ratio of magnetic moments of the new coil and the original coil

15 A straight wire of length L is bent into semicircular loop. Use biot -savart law to deduce an expression for the

magnetic field at its center due to current I passing through it .

16 Two long parallel straight wires X and Y separated by a distance of 5 cm in air carry currents of 10A and 5A

respectively in opposite direction. Calculate the magnitude and direction of the force on a 20 cm length of the

wire Y.

17 If the current sensitivity of a moving coil galvanometer is increased by 20% ,

its resistance also increased by 1.5 times,. How will the voltage sensitivity of

galvanometer be affected.

18 Two identical circular wires P and Q each of radius R and carrying current ‘I’ are kept in

perpendicular planes such that they have a common centre as shown in the figure. Find the

magnitude and direction of the net magnetic field at the common centre of the two coils.

19 What are permanent magnets? What is an efficient way of preparing a permanent magnet?

Write two characteristic properties of materials which are required to select them for

permanent magnets.

20 Two wires of equal lengths are bent in the form of a circle and a square. These are suspended in a uniform

magnetic field and the same current is passed through them. Which loop will experience greater torque?

21 The magnetization curve is irreversible .Explain

22 A long straight wire carries a current of 10A from east to west. What is the magnitude and direction of the field B

at a point 50 cm above the wire?

23 Diffentiate between Para and ferro magnetic materials. (at least four points)

24 Explain, why a wire of irregular shape turning into a circular shape, when suddenly a magnetic field applied

perpendicular to its plane.

25 A particle of mass m and charge q moves at right angle to a uniform magnetic field. Plat a graph showing the

variation of the radius of circular path described by it with increase of in its charge q.

26 A charged particle having a charge q , moving with a speed v , parallel to wire , at a distance d from it in a

direction opposite to the current. What is the force experienced by the charge and what is its direction?

27 A uniform magnetic field gets modified as shown below when two specimens X and Y are placed in it. a.Identify

whether specimens X and Y are diamagnetic, paramagnetic or ferromagnetic.

b. (iii) How is the magnetic permeability of specimen X different from that of specimen Y?

28 A wire AB is carrying a steady current of 10 A and is lying on the table. Another wire CD carrying 6 A is held

directly above AB at a height of 2 mm. Find the mass per unit length of the wire CD so that it remains suspended

at its position when left free. Give the direction of the current flowing in CD with respect to that in AB. [Take the

value of g = 10 ms−2

]

29 A circular coil of N turns and diameter "d" carries a current I. .It is wounded and rewound to make another coil of

diameter "2d" , current I remaining the same . Calculate the ratio of magnetic moments of the new coil and the original

coil

30 A straight wire of length L is bent into semicircular loop. Use biot -savart law to deduce an expression for the

magnetic field at its center due to current I passing through it .

31 Using Ampere’s circuital law , obtain expression for magnetic field along the axis of a current carrying solenoid of

length l and having N umber turns.

32 Two long parallel straight wires X and Y separated by a distance of 5 cm in air carry currents of 10A and 5A

respectively in opposite direction. Calculate the magnitude and direction of the force on a 20 cm length of the wire Y .

33. Can a Moving Coil Galvanometer can be used to detect an A.C. in a circuit .Give reason.

34. A charge particle moving in a magnetic field penetrates a layer of lead and thereby loses half of its kinetic energy.

How does the radius of curvature of its path change?

35. Earth’s Magnetic Field does not affect working of moving Coil Galvanometer. Why?

36. A proton is about 1840 times heavier than an electron. What will be its kinetic energy when it is accelerated by a

potential difference of 1KV?

37 . Find the magnetic moment of a wire of length l carrying current I bent in the form of a circle.

SECTION-C (THREE MARKS)

1. A rectangular coil 0.1m x 0.2m having 100 turns is rotating in a uniform magnetic field 0.003 T with the frequency of 1200 rpm about an axis normal to the magnetic field. Find the emf produced in the coil. 2. A particle of charge q and mass m is moving with velocity V . It subjected to uniform magnetic field B directed perpendicular to its velocity. Show it describe a circular path .Write expression for its radius. 3. A long straight wire of a circular cross-section (radius a) carrying steady current I. The current I is uniformly distributed across this cross-section. Calculate the magnetic field in the region r < a . 4. State Ampere’s circuital law. Use it to find magnetic field due to a straight current carrying solenoid? 5. Distinguish the magnetic properties of dia, para and ferro magnetic substance. (at least 3 each with example)

6. The hysteresis loop of a material A has smaller area than that of material B. (a) Which material will dissipate greater heat energy and why ? (b) Which material has more retentively and which material has more coercively? (c) Which of the material is most suitable for making transformer cores ? Hence deduce an expression for the force experienced per unit length by each conductor. 7. (a) Two long straight parallel conductors ‘a’ and ‘b’, carrying steady currents Ia and Ib are separated by a distance d. Write the magnitude and direction of the magnetic field produced by the conductor ‘a’ at the points along the conductor ‘b’. If the currents are flowing in the same direction, what is the nature and magnitude of the force between the two conductors? (b) Show with the help of a diagram how the force between the two conductors would change when the currents in them flow in the opposite directions. 8. Define current sensitivity and voltage sensitivity of a galvanometer. Increasing the current sensitivity may not necessarily increase the voltage sensitivity of a galvanometer. Jus 9 Draw a labeled diagram of a moving coil galvanometer and explain its working, what is the function of radial

magnetic field inside the Coil and soft iron core? 10 Draw a schematic sketch of the cyclotron. State its working principle. Show the cyclotron frequency is

independent of the velocity of the charged particles.

11 Derive an expression for the torque experienced by a rectangular loop carrying a steady current I and placed in

a uniform magnetic field B .Indicate the direction of the torque acting on the loop.

12 Derive an expression for force per unit length between two long straight parallel current carrying conductors.

Hence defines one Ampere.

13 Using Biot -savat law derive an expression for the magnetic field of at a distance x along the axis from the center

of a current carrying circular loop.

14 Define the term: Magnetic Dipole moment of a current loop. Write the expression for the magnetic moment

when an electron revolves at a speed ‘v’, around an orbit of radius ‘r’ in hydrogen atom

15 In a cyclotron, a magnetic field induction of 0.4 T is used to accelerate protons. How rapidly should the electric

field between the dee be reversed? The mass and charge of proton are 1.67 X 10 -28

kg and

1.6 X 10-19

C respectively.

16 A solenoid 60 cm long and of radius 4.0 cm has 3 layers of winding of 300 turns each. A 2.0 cm long wire of mass

25 g lies inside the solenoid (near its centre) normal to its axis: both the wire and the axis of the solenoid are in

the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to an external

battery which supplies a current of 6.0 A in the wire. What value of current (with appropriate sense of

circulations) in the windings of the solenoid can support the weight of the wire?

17 How will a dia-, para- and a ferromagnetic materials behave when kept in a non-uniform external magnetic field

? Give one example of each of these materials.

18 Derive an expression for the torque on a current carrying loop in a uniform magnetic

field.

19 Two small identical circular coils marked 1 and 2 carry equal currents and are placed

with their geometric axes perpendicular to each other as shown in the figure.

Derive an expression for the resultant magnetic field at O.

20 A Voltmeter, an ammeter and a resistance are connected in series with a battery. There is some deflection in

voltmeter but the deflection of ammeter is zero. Explain why?

21 How does a ferromagnetic material change its Magnetic properties if it is heated beyond its curie temperature?

22. Two long straight wires are set parallel to each other. Each carries a current I in the same direction and the

separation between them is 2r. What is the intensity of the magnetic field mid way between them?

23 A circular loop of radius R carrying current I ,lies in X-Y plane with its centre at origin. What is the total magnetic flux

through X-Y plane?

24 A circular current carrying coil has a radius R. What is the distance from the centre of thecoil on its axis where the

magnetic field is 1/8 th of its value at the centre?

25. A magnetic needle suspended freely in a uniform magnetic field experiences torque but no net force. A nail made up

of iron kept near a bar magnet experience a force of attraction and torque .Give reason.

26.A particle with charge q moving with velocity v in the plane of the paper enters a uniform magnetic field B acting

perpendicular to the plane of the paper. Deduce an expression for the time period of the charge as it moves in a circular

path in the field .

27 What is the magnetic field produced at the centre of curvature of an arc of wire of radius carrying current I subtends

an angle P /2radians at its centre.

28. When current is flowing through two parallel conductors in the same direction they attract while two beams of

electrons moving in the same direction repel each other. Why?

29. Draw diagrams to show behavior of magnetic field lines near a bar of (i) Aluminum (ii)copper and (iii) mercury cooled

to a very low temperature 4.2 K


1.Draw a schematic sketch of a cyclotron. Explain briefly how it works and how it is used to accelerate the charged particles. (i) Show that time period of ions in a cyclotron is independent of both the speed and radius of circular path. (ii) What is resonance condition? How is it used to accelerate the charged particles? 2. (a)With the help of diagram , explain the principle and working of moving coil galvanometer. (b)What is the importance of a radial magnetic field and how is it produced? (c) Why is it that while using a moving coil galvanometer as a voltmeter a high resistance in series is required where as in an ammeter a shunt is used? 3. State Biot- savart law, giving the mathematical expression for it. Use this law to derive the expression for the magnetic field due to the circular coil carrying current at a point along its axis. How does a circular loop carrying current behave as magnet? . 4 )Explain , giving reasons the basic difference in converting a galvanometer into (i) a voltmeter and (ii) an ammeter

(b) Two long straight parallel conductor carrying steady current I1 and I2 are separated by a distance d . Explain briefly

with the help of suitable diagram, how the magnetic field due to one force acting between the two conductors. Mention

the nature of the force

5. Draw a schematic sketch diagram of cyclotron. State its working principle .Describe briefly how it is used to accelerate

the charge particle. Show that the period of revolution of an ion is independent of its speed or radius of the orbit. Write

two important use of cyclotron.

6. State Ampere's circuital law. (b)Use it to derive an expression for magnetic field inside in side , along the axis of an air

cored solenoid.

(c)Sketch the magnetic field line for a finite solenoid .How are these field lines different form the electric field lines from

an electric dipole.

.

7 A straight horizontal conducting rod of length 0.5 m and mass 50 g is suspended by two vertical wires at its ends. A

current of 5A is set up in the rods through the wires.(i) What magnetic field should be set up normal to the conductor in

order that the tension in the wires is zero?(ii)What will be the tension in the wire if the direction of current is reversed

keeping the magnetic field same as before?(neglect the mass ; g=10m/s2 )

29. Draw a neat and labeled diagram of a cyclotron . State the underlying the principle and explain how a positively

charged particle will get accelerated. Show mathematically the cyclotron frequency does not depend upon speed of the

particle.

UNIT-IV (INDUCTION AND AC) SECTION-A (ONE MARK)

1. A bar magnet is moved in the direction indicated by the arrow between two coils P Q and CD. Predict the direction of induced current in each coil. 2. Predict the direction of induced current in metal rings 1 and 2 laying in the same plane where current in wire increasing steadily. 3. A flexible wire of irregular shape, abcd, as shown in the figure, turns into a circular shape when placed in a region of magnetic field which is directed normal to the plane of the loop away from the reader. Predict the direction of the induced current in the wire. 4. Why is the use of AC voltage preferred over DC voltage? 5. A device ‘X’ is connected to an a.c. source V = Vo sin ωt. The variation of voltage, current and power in one complete cycle is shown in the following figure. (i) Which curve shows power consumption over a full cycle? (ii) Identify the device ‘X’.

6 Define the term 'wattles current'

7 When alternating current is passed through a moving coil galvanometer, it shows no deflection, why?

8 How can the power factor of a series LCR circuit be improved? Suggest any one method.

9 The power factor of an a.c circuit is 0.5. What will be the phase difference between voltage and current in this

circuit?

10 When a lamp is connected to an alternating voltage supply, it lights with the same brightness as when

connected to a 12V DC battery .What is the peak value of alternating voltage source?

11 A bulb and a capacitor are connected in series to an a.c source of variable frequency .How will the brightness of

the bulb change on increasing the frequency of t

12 A conducting loop is held above a current carrying wire ‘PQ’ as shown in the figure.

Depict the direction of the current induced in the loop when the current in the wire PQ is

constantly increasing.

13 The electric current flowing in a wire in the direction from

out the direction of the induced current in the metallic loop kept above the wire as

shown.

14 The peak value of emf in a c. is E

complete cycle.

15 Define the self-inductance of a coil. Write its SI units.

16 State Faraday’s law of electromagnetic induction.

17 What is the function of step -up transformer?

18 .How can the power factor of a series LCR circuit be improved? Suggest any one method

19 The power factor of an a.c circuit is .5 . What will be the phase difference between voltage and current in this

circuit?

20 A bulb and a capacitor are connected in series to an a.c source of variable frequency .How will the brightness of

the bulb change on increasing the frequency of the a.c source? Give reason.

21 A choke coil and a bulb are connected in series to a d.c source. The bulb shines brightly .How does the

brightness change when an iron core is inserted in the choke coil?

22 A vertical magnetic poles falls down through the plane of the magnetic meridian. Will any e.m.f be produced

between its ends? Give reason for your answer.

23 Power factor of an ac circuit is 0.5. What will be the phase difference between voltage and current in the circuit?

24 Which device will you use to step up/ step down a.c voltage?

25 The e.m.f of ac source is given by the expression E = 300 sin 314 t volts. Write the values of an peak voltage and

frequency of source.

26 Which is the best method of reducing current in an a.c circuit and why

27 Write expression for the average value of the a.c voltage V = V

28 An electrical element X, when connected to an alternating voltage source, has the current through it leading the

voltage by π/2 rad. Identify X and write an expression for its reactance.

1. State Faraday’s laws of electromagnetic induction. An velocity V perpendicular to B and also perpendicular to L. Find the induced emf betw ends of the rod. 2. Why the core of a transformer is made of a material whose hysteresis loop is narrow?3. Show that the energy stored in an inductor L ,when a current I is established through it is½ LI4. What is the power dissipation in an ac circuit in which voltage and current are given byV=200 sin (ωt +

) and I = 8 sin ωt ?

5. In the circuit given R represent an electric bulb. If frequency ν= (w/2π) of supplied is doubled, how should the value of C and L would be changed ,so that the glow of bulb remain unchanged..

6. Show that Lenz's law is in accordance with law of conservenergy.

7. A square loop of side 10 cm and resistance 0.5 uniform magnetic field of 0.10 T is set up across the plane in the north magnetic field is decreased to zero in 0.70 s at a steady rate. Determine the magnitudes of induced emf. 8. For circuits used for transporting electric power, a low power factor implies large power loss in transmission. Explain. 9. Derive an expression for a self-inductance of a long air of turns N.

connected to a 12V DC battery .What is the peak value of alternating voltage source?

A bulb and a capacitor are connected in series to an a.c source of variable frequency .How will the brightness of

the bulb change on increasing the frequency of the a.c source? Give reason.

A conducting loop is held above a current carrying wire ‘PQ’ as shown in the figure.


g in a wire in the direction from B to A is decreasing. Find

current in the metallic loop kept above the wire as

peak value of emf in a c. is E0. Write its (i) rms and (ii) average value over a

inductance of a coil. Write its SI units.

State Faraday’s law of electromagnetic induction.

up transformer?

.How can the power factor of a series LCR circuit be improved? Suggest any one method

The power factor of an a.c circuit is .5 . What will be the phase difference between voltage and current in this


increasing the frequency of the a.c source? Give reason.

A choke coil and a bulb are connected in series to a d.c source. The bulb shines brightly .How does the

brightness change when an iron core is inserted in the choke coil?

alls down through the plane of the magnetic meridian. Will any e.m.f be produced

between its ends? Give reason for your answer.

Power factor of an ac circuit is 0.5. What will be the phase difference between voltage and current in the circuit?

e will you use to step up/ step down a.c voltage?

The e.m.f of ac source is given by the expression E = 300 sin 314 t volts. Write the values of an peak voltage and

Which is the best method of reducing current in an a.c circuit and why?

Write expression for the average value of the a.c voltage V = Vosinωt over the time interval t =0 and t = π/ω.

An electrical element X, when connected to an alternating voltage source, has the current through it leading the

and write an expression for its reactance.

SECTION-B (TWO MARKS) State Faraday’s laws of electromagnetic induction. An insulating rod of length L falling with a velocity V perpendicular to B and also perpendicular to L. Find the induced emf betw

2. Why the core of a transformer is made of a material whose hysteresis loop is narrow?3. Show that the energy stored in an inductor L ,when a current I is established through it is½ LI4. What is the power dissipation in an ac circuit in which voltage and current are given by


R represent an electric bulb. If frequency ν= (w/2π) of supplied is doubled, how should the value of C and L would be changed ,so that the glow of bulb remain unchanged.. Show that Lenz's law is in accordance with law of conservation of

7. A square loop of side 10 cm and resistance 0.5 Ω is placed vertically in the east-west plane. A uniform magnetic field of 0.10 T is set up across the plane in the north-east direction. The

field is decreased to zero in 0.70 s at a steady rate. Determine the magnitudes of

8. For circuits used for transporting electric power, a low power factor implies large power loss in

inductance of a long air- cored solenoid of length L and number



. Write its (i) rms and (ii) average value over a

.How can the power factor of a series LCR circuit be improved? Suggest any one method

The power factor of an a.c circuit is .5 . What will be the phase difference between voltage and current in this


A choke coil and a bulb are connected in series to a d.c source. The bulb shines brightly .How does the

alls down through the plane of the magnetic meridian. Will any e.m.f be produced

Power factor of an ac circuit is 0.5. What will be the phase difference between voltage and current in the circuit?

The e.m.f of ac source is given by the expression E = 300 sin 314 t volts. Write the values of an peak voltage and

sinωt over the time interval t =0 and t = π/ω.

An electrical element X, when connected to an alternating voltage source, has the current through it leading the

rod of length L falling with a velocity V perpendicular to B and also perpendicular to L. Find the induced emf between the two

2. Why the core of a transformer is made of a material whose hysteresis loop is narrow? 3. Show that the energy stored in an inductor L ,when a current I is established through it is½ LI2.. 4. What is the power dissipation in an ac circuit in which voltage and current are given by


west plane. A east direction. The

field is decreased to zero in 0.70 s at a steady rate. Determine the magnitudes of

8. For circuits used for transporting electric power, a low power factor implies large power loss in

cored solenoid of length L and number

10. In a series LCR circuit with an ac source of effective voltage 50 V, frequency v =50 /π Hz, R = 300Ω, C = 20 µF and L = 1.0 H. Find the rms current in the circuit. 11.Explain briefly how the phenomenon of resonance in the circuit can be used in the tuning mechanism of a radio or a TV set.

12 State the underlying principle of a transformer. How is the large scale transmission of electric energy over long

distance done with the use of transformers?

13 What are eddy currents? Write any two applications of eddy currents.

14 Two identical loops, one of copper and other of aluminum, are rotated with the same angular speed in the same

magnetic field. Compare (i) the induced emf and (ii) the current produced in the two coils. Justify your answer.

15 Prove that an ideal inductor does not dissipate power in an a.c. circuit.

16 Write the expression for frequency of an ideal LC circuit. In an actual circuit, why do the oscillations ultimately

die away?

17 Define mutual inductance between two long co-axial solenoid .Find out the expression for the mutual

inductance of inner solenoid of length l having the radius r1 and r2 and the number of turns n1 per unit length

due to the second outer solenoid of same length and n2 number of turns per unit length.

18 A current induced in coil c1 due to the motion of current carrying coil c2

(a) write any two ways by which a large deflection can obtained in the galvanometer G .

(b) Suggest an alternative device to demonstrate the induced current in place of galvanometer.

19 Magnetic flux of 5 μWb is linked with a coil, when a current of 1mA flows through it .What is the self-inductance

of the coil.

20 Explain the principle in which a metal detector used at airports for security reasons works.

21 Write two advantages of a.c over d.c

22 An inductor `L’ of reactance XL, is connected in series with a bulb `B’ to an a.c. source. Briefly explain how does

the brightness of the bulb change, when (i) numbers of turns of the inductor is reduced and (ii) a capacitor of

reactance XC= XL is included in series in the same circuit.

23 Two bar magnets are quickly moved towards a metallic loop

connected across a capacitor ‘C’ as shown in the figure. Predict the

polarity of the capacitor.

24 A rod of length 50 cm moving horizontally at a speed of 10m/s at a

place where earth vertically component is 0.4G. Find the potential difference produced at the end of rod

25 Prove that an ideal capacitor, in an a.c. circuit does not dissipate power.

26 Derive an expression for the impedance of an a.c. circuit consisting of a capacitor and a resistor.

27 Define mean value of AC (over a half cycle) and derive an expression for it.

28 Define RMS value of AC and derive an expression for it.

29 Show that the average value of AC over a complete cycle is zero.

30 Draw the graphs showing the variation of reactance of (a) a capacitor and (b) an inductor with the

frequency of an a.c. circuit.

31 Derive an expression for induced e.m.f produced by changing the area of a rectangular coil placed perpendicular

to the magnetic field.

32 Derive an expression for the instantaneous value of induced e.m.f in a coil when it is rotated in a uniform

magnetic field at a uniform angular velocity n. How does the e.m.f vary when the coil rotates through an angle

of 2π ? .

33 How are eddy currents produced? Give two applications of eddy currents.

34 Derive expression for the self inductance of a long solenoid of length having N turns.

35 A radio frequency choke is air cored coil whereas an audio frequency choke is iron cored. Give reasons for this

difference.

36 Define Mutual induction. Write its S.I unit. Give two factors on which the coefficient of mutual inductance

between a pair of coils depends.

37 The magnetic flux through a coil perpendicular to its plane is varying according to the relation Φ = (5 t3 + 4 t

2 + 2t

-5) Weber. Calculate the induced current through the coil at t = 2 s of the resistance of the coil is 5Ω.

SECTION-C (THREE MARKS) 1. A coil of inductance 0.5 H and resistance 100Ω is connected to a 240 V; 50 Hz Ac supply. Calculate the maximum current in the coil and the time lag between maximum voltage and maximum current? 2. What is Q – factor of LCR circuit. Obtain the resonant frequency 0 of a series LCR circuit when L = 2.0H , C = 32F and R = 10 . Also find out the Q-Factor of the circuit. 3. Two concentric circular coils, one of small radius r1 and the other of large radius r2, such that r1 << r2, are placed co-axially with centers coinciding. Obtain the mutual inductance of the arrangement.

4 How is the mutual inductance of a pair of coils affected when: (i) Separation between the coils is increased? (ii) the number of turns of each coils is increased ? (iii) a thin iron sheet is placed between the two coils ,other factors remaining the same 5. When a circuit element ‘X’ is connected across an a.c source of 220 v, a current of 0.5 A flows through it and this current is found to be in phase with applied voltage. When the same source is applied across another element ‘Y’ the current remains the same but it leads the voltage by 900. Identify the elements X and Y. Find the current that flows in the circuit when the series combination of X and Y is connected across the same a.c voltage.

6. When 100 volts d.c is applied across an inductor, a current of 1A flows through it. If the same inductor is connected across 100 v a.c. source, a current reduces to 0.5 A. Why is the current reduced in later case? Calculate the reactance and phase angle between current and EMF if the frequency of ac is 50 Hz. 7. Name the element present in a circuit if current in the circuit leads the emf by a phase angle 90 degree. Write the expression for reactance of such circuit and show graphically how its reactance is affected on increasing the frequency of AC. 8. Explain the term 'capacitive reactance'. Show graphically the variation of capacitive reactance with frequency of the applied alternating voltage. An a.c. voltage E = E0 Sinωt is applied across a pure capacitor of capacitance. Show mathematically that the current flowing through it leads the applied voltage by a phase angle of π/2.

9. A toroidal solenoid with air core has an average radius of 15 cm, area of cross-section 12 cm2 and has1200 turns. Calculate the self-inductance of the toroid. Assume the field to be uniform across the cross-section of the toroid. 10. An inductor of unknown value, a capacitor of 100mF and a resistor of 10W are connected in series to a 200 V, 50 Hz

a.c. source. It is found that the power factor of the circuit is unity. Calculate the inductance of the inductor and the

current amplitude.

11 A coil of number of turns N , area A , is rotated at a constant angular speed ω, in a uniform magnetic field B,

and resistor R .Deduce expression for ;(i) Maximum emf induced in the coil (ii) power dissipation in the coil .

12 State Faraday's laws of electromagnetic induction. Hence show that the magnitude of motional e.m.f across a

straight wire is| e | = B Iv, where e, B ,l ,v have their usual meanings.

13 A square loop of side 12 cm with its sides parallel to X and Y-axes is moved with a velocity of 8 cm/s in positive x-

direction in an environment containing a magnetic field in the positive z-direction. The field is neither uniform in

space nor constant in time. It has a gradient of 10-3

T/cm along negative x-direction,. Find the emf and

magnitude of the induced current in the loop if its resistance is 4.5 m Ω.

14 With the help of phase diagram derive the expression for impedance in a a.c circuit containing a resistor and an

inductor. Find the phase difference of emf and current.

15 A metallic rod of length l is rotated at an angular speed ω ,normal to uniform magnetic field B. Derive

expressions for the(i) emf induced in the rod (ii) heat dissipation , if the resistance of the rod is R.

16 A series LCR circuit is connected to an a.c. source. Using phasor diagram , derive the expression for the

impedance of the circuit.

17 Plot a graph to show the variation current with the frequency of the source, explaining the nature of its

variation.

18 Use Lenz' law to find the direction of induced emf in a coil when (a) a north pole is brought towards the coil (b)

north pole taken away from the coil (c) A south pole is brought towards the coil and (d) a south pole is taken

away from the coil, Draw illustrations in each case.

19 Show that the current and voltage are in phase in an ac circuit containing resistance only.

20 Deduce the phase relationship between current and voltage in an ac circuit containing capacitor only.

21 Distinguish between resistance, reactance and impedance.

22 Define quality factor (Q factor) of resonance and derive an expression for it.

23 Describe the various losses in a transformer and explain how the losses can be minimized.

24 Draw a plot showing the variation of the current I as a function of angular frequency ‘ω’ of the applied ac source

for the two cases of a series combination of (i) inductance L1, capacitance C1 and resistance R1 and (ii)

inductance L2, capacitance C2 and resistance R2 where R2 > R1. Write the relation between L1, C1 and L2, C2 at

resonance. Which one, of the two, would be better suited for fine tuning in a receiver set? Give reason

25 Explain the term ‘Inductive reactance’. Show the graphically the variation of inductive reactance with the

frequency of the applied alternating voltage. An a.c. voltage E=Eosin ωt is applied across a pure inductor of

inductance L. Show mathematically that the current flowing through it lags behind the applied voltage by a

phase angle of /2.

26 Describe briefly, with the help of a labeled diagram, working of a step-up transformer. A step-up transformer

converts a low voltage into high voltage. Does it not violate the principle of conservation of energy? Explain.

27 A coil of number of turns N , area A , is rotated at a constant angular speed Ω, in a uniform magnetic field B, and

resistor R .Deduce expression for ;(i) Maximum emf induced in the coil (ii) power dissipation in the coil

28 A 15 .0 µF capacitor is connected to a 220V, 50HZ source. Find the capacitive reactance.

29 A circuit containing a 80 mH inductor and a 60 μF capacitor in series is connected to a 230 V, 50 Hz supply. The

resistance of the circuit is negligible. (a) Obtain the current amplitude and rms values.

(b) Obtain the rms values of potential drops across each element.(c) What is the average power transferred to the

inductor ?

30 Explain the basic principle, description and working of a.c generator with neat labeled diagram.

31 A rectangular coil of N turns and area of cross section A, is held in time varying magnetic field given by B = B0 sin

ωt , with plane of coil normal to the magnetic field .Deduce an expression for the e.m.f induced in the coil.

32 A wheel with 10 metallic spokes each 0.5 m long is rotated with a speed of 120 rev/min in a plane normal to the

horizontal component of earth’s magnetic field at a place. If BH = 0.4 G at the place .What is the induced emf

between the axle and the rim of the wheel?

33 Two circular coils, one of radius r and the other are placed coaxially with their centre coinciding. For R>>r, obtain

an expression for the mutual inductance of the arrangement.

34 A pure conductor is connected across an a.c source. Show mathematically that the current in it lags behind the

applied emf by a phase angle of π/2.What is the inductive reactance?

35 Derive the expression for magnetic energy stored in a inductor/ solenoid.

36 Explain the LCR circuit with neat diagram. State the condition under which the phenomenon occurs in a series

LCR circuit. Plot a graph showing variation of current with frequency of a.c source in a series LCR circuit.

How does the impedance of an LCR series circuit varies with the frequency of

37 Figure (a), (b) and (c) Show three alternating circuits with having frequency how the phase between current

and voltage are related.

(a) (b) (c)


1. (i) What is meant be impedance? (ii) A series LCR circuit is connected to ac source having voltage V= V0sin ωt. Derive the expression for impedance ,instantaneous current and its phase relationship to the applied voltage. Find the expression for resonant frequency. 2. With the help of a diagram explain the construction and working of a transformer . Describe the various losses of transformer and how can these losses be reduced ? How it is useful for long distance transmission of electrical energy. 3. (a)Show that in an AC circuit containing pure inductor only, instantaneous voltage leads the corresponding currents by 900. (b)Show that no power consumed in this circuit, over one complete cycle. (c) A lamp is connected in series with a capacitor. What happens to the glow of bulb if the capacitance of the capacitor is reduced? 4. (a) With the help of a diagram, explain the principle and working of a device which produces current that reverses its direction after regular intervals of time. (b) If a charged capacitor C is short circuited through an inductor L, the charge and current in the circuit oscillate simple harmonically. (i) In what form the capacitor and the inductor stores energy? (ii) Write two reasons due to which the oscillations become damped. 5. (a) Figure shows the variation of resistance and reactance versus angular frequency. Identify the curve which corresponds to inductive reactance and resistance. (b) Show that series LCR circuit at resonance behaves as a purely resistive circuit. Compare the phase relation between current and voltage in series LCR circuit for (i) XL > XC (ii) XL = XC using phasor diagrams. (c) What is an acceptor circuit and where it is used?

PAGE-8

UNIT-V (electromagnetic wave) SECTION-A (ONE MARK)

1. What is the ratio of speed of gamma rays and radio waves in vacuum? 2. Which radiation is used for (i) checking of currency (ii) TV communication ? 3. Give any two applications of X-rays. 4. What is the relation between electric and magnetic field in an E.M wave? 5. State the part of the electromagnetic spectrum to which each belongs. (a) 5890 Å - 5896 Å [double lines of sodium] (b) 21 cm (wavelength emitted by atomic hydrogen in interstellar space. 6. Arrange the following electromagnetic waves in order of increasing frequency: γ-rays, microwaves, infrared rays and ultraviolet rays. 7. What are the directions of electric and magnetic field vectors relative to the direction of propagation of electromagnetic waves? 8. To which part of the electromagnetic spectrum does a wave of frequency 5 × 1011 Hz belong? 9. Which remain constant for all electromagnetic waves? 10. Write two uses of X-ray.

11 How are X- rays produced? 12 Write the following radiations in ascending order in respect of their frequencies; X-ray , microwave 13 Name the electromagnetic radiations which can be produced by klystron or a magnetron valve.

14 Which part of electromagnetic spectrum is used in radar system?

15 How micro waves produced. Name the part of the electromagnetic spectrum of wavelength 10-2 m

and mention its one application.

16 Welders wear special goggles or face masks with glass windows to protect their eyes from

electromagnetic radiations. Name the radiations and write the range of their frequency.

17 Which radiation is used to (i) check currency (ii) TV communication.

18 A plane electromagnetic wave of frequency 25 MHz travels in a free space along the X- direction. At a

particular point in space and time the electric field is E=6.3 J V/m .Calculate B at this point.

19 Draw sketch of a plane electromagnetic wave propagating along the z-direction .Depict clearly the

directions of electric and magnetic fields varying sinusoid ally with z.

20 What are the directions of electric and magnetic fields vectors relative to each other and relative to

the direction of propagation of electromagnetic waves?

21 How are radio waves produced?

22 What is common between different types of e.m. radiations ?

SECTION-B (TWO MARKS) 1Prove that the total energy density of an electromagnetic wave is twice the energy density of electrfield

2. Describe briefly how electromagnetic waves are produced by oscillating charges 3Considering the case of a parallel plate capacitor being charged, show how one is required to generalize Ampere’s circuital law to include the term due to displacement current. 4A capacitor, made of two parallel plates each of plate area A and separation d, is being charged by an external ac source. Show that the displacement current inside the capacitor is the same as the current charging the capacitor.

5 Draw sketch of a plane electromagnetic wave propagating along the z-direction .Depict clearly the directions of electric and

magnetic fields varying sinusoid ally with z.

7 List any four characteristics of an electromagnetic wave .

8 When an ideal capacitor is charged by a dc battery, no current flows. However when an a.c. source is

used, the current flows continuously. How does one explain this, based on the concept of

displacement current?

9 A parallel plate capacitor is being charged by a time varying current. Explain briefly how Ampere’s

circuital law is generalized incorporate the effect due to the displacement current.

10 What is meant by the transverse nature of electromagnetic waves? Draw a diagram showing the

propagation of an electromagnetic wave along the x-direction, indicating clearly the directions of the

oscillating electric and magnetic fields associated with it.

SECTION-C (THREE MARKS) 1. In a plane electromagnetic wave the electric field oscillate at a frequency of 2.0x1010Hz and amplitude is 48Vm-1 (a) What is wave length of a wave ? (b) What is amplitude of magnetic field? 2. The magnetic field in a plane electromagnetic wave is given

By = 2 x 10–7 Sin (0.5x10–3 + 1.5x1011t) T . (i) What is the wavelength and frequency of the wave? (ii) Write an expression for electric field. 3. Name the constituent radiation of electromagnetic spectrum which (i) Is used in satellite communication. (ii) Is used for studying crystal structure. (iii) Is similar to the radiations emitted during decay of radioactive nuclei. (iv) Has its wavelength range between 390 nm and 770 nm. (v) Is absorbed from sunlight by ozone layer. (vi)Produces intense effect. 4. Suppose that the electric field part of an electromagnetic wave in vacuum is E = (3.1 N/C) cos [(1.8 rad/m) y + (5.4 × 106 rad/s)t]ˆi . (a) What is the direction of propagation? (b) What is the wavelength λ ? (c) What is the amplitude of the magnetic field part of the wave? (d) Write an expression for the magnetic field part of the wave. 5. Name the following constituent radiations of electromagnetic spectrum which

(i) Produce intense heating effect. (ii) Is absorbed by the ozone layer in the atmosphere. (iii) Is used for studying crystal structure. Write one more application for each of these radiations 6 A capacitor of 2µf is charged to 20 volt and then suddenly short-circuited by a coil of negligible resistance and of inductance 8µH Calculate (i) the maximum amplitude and (ii) the frequency of resulting oscillation. 8 Write order of frequency range and one use of each of the following electromagnetic radiations (i) Micro waves (ii)

Ultra –violet rays( iii)Gamma rays. .

9 The oscillating electric field in a plane electromagnetic wave is given by EY= 30 sin (2×1011

t +300 π x ) V m-1

(i)

Calculate the wavelength of the electromagnetic wave. (ii) Write down the expression for the

oscillating magnetic field.

.

10 Explain the inadequacy of Ampere's circuital law

11 Describe Hertz experiment to demonstrate the production of electromagnetic waves.

12 Write any five electromagnetic waves in the order of decreasing frequency and write any two

properties and uses of each.

( OPTICS) UNIT-VI

SECTION-A (ONE MARK) 1. How would the angular separation of interference fringes in Young’s double slit experiment changes when the distances between the slits screen is doubled. 2. If the angle between the passes axes of a polarizer and analyzer is 450.Write the ratio of the intensities of the original light and the transmitted light after passing through the analyzer. 3. What type of wave front will emerge from a (i) point source, and (ii) line source? 4. A lens of glass is immersed in water. What will be the effect on the power of lens ? 5. An object is placed in front of convex lens made of glass. How does the image distance vary if the refractive index of the medium is increased in such a way that still it remains less than the glass? 6.How does the fringe width get affected, if the entire experimental apparatus of Young is immersed in water ? 7.Write the conditions to obtain sustained interference fringes pattern.

8. What is resolving power of microscope? Write expression for it.

9A biconvex lens made of transparent material of refractive index 1.5 is immersed in water of refractive index 1.3 .Will

the lens behave as a converging or diverging lens ? Give reason.

10. A concave lens of refractive index 1.5 is immersed in a mediu

the lens?

11 A glass lens of refractive index 1.5 is placed in a through of liquid. What must be the refractive index of the liquid in

order to make the lens disappear

13 If the angle between the pass axis of

light and the transmitted light after passing through the analyzer.

14 Unpolarized light is incident on a plane surface of refractive index μ at angle i. If the refle

polarised, write the relation between the angle i and refractive index μ.

15 At what angle of incidence should a light beam strike a glass slab of refractive index

and the refracted rays are perpendicu

16 A concave lens of focal length -20 cm is cut into two identical plano concave lens . What is the focal length of

each part?

17 Violet light is incident on a thin convex lens. If this light is rep

power of the lens would change?

18 State with reason why two independent sources of light cannot be considered as coherent sources.

19 State the criteria for the phenomenon of total internal reflection of lig

20 How does focal length of a lens change when red colour light incident on it is replaced by violet light ? Give

reason for your answer.

21 Sketch the variation of intensity of interference pattern in Young’s double slit experiment.

22 What is the ratio of fringe width of bright and dark fringes in Young’s double slit experiment?

23 What is the effect on interference fringes in Young’s double slit experiment if one slit is covered?

24 A polarizer and analyzer are so oriented that intensity of transmit

through 600 what fraction of maximum light is transmitted?

25 Draw a graph showing variation of intensity of polarized light transmitted by an analyzer.

26 Bubbles of a colourless soap solution appear colored in sun light. Why?

27 What happens to the energy at destructive interference in interference pattern?

1 Two polarizing sheets in the path of initially unpolarized light. The polarizing direction of first sheet is parallel to x-axis and that of second sheet is 60 fraction of intensity of light emerges from the system. 2 . Describe two uses of total internal reflection3 . Draw a schematic diagram of a reflecting telescope. of a reflecting telescope. 4 . A convex lens of focal length 10 cm is placed coaxially 5 cm awlength 10 cm. If an object is placed 30 cm in front of theimage formed by the combined system.

5 A convex lens is placed in water. Will the focal length change? Explain.6 The refractive index of a material of a concave lens is n index n2 . A parallel beam of light is incident on the lens. Trace the path of ray of light when (i) n1 = n2 (ii) n2 > n1 7 . Three light rays red (R), green (G) and blue (B) are incident on the right angled prism abc at face ab. The refractive indices of the material of the prism for red, green and blue wavelengths are respectively1.39, 1.44 and 1.47. Trace the paths of any two

A biconvex lens made of transparent material of refractive index 1.5 is immersed in water of refractive index 1.3 .Will

the lens behave as a converging or diverging lens ? Give reason.

. A concave lens of refractive index 1.5 is immersed in a medium of refractive index 1.65. What is the nature shown by

A glass lens of refractive index 1.5 is placed in a through of liquid. What must be the refractive index of the liquid in

xis of polarizer and the analyzer is 45°, write the ratio of the intensities of original

light and the transmitted light after passing through the analyzer.

Unpolarized light is incident on a plane surface of refractive index μ at angle i. If the refle

polarised, write the relation between the angle i and refractive index μ.

At what angle of incidence should a light beam strike a glass slab of refractive index √3and the refracted rays are perpendicular to each other?

20 cm is cut into two identical plano concave lens . What is the focal length of

Violet light is incident on a thin convex lens. If this light is replaced by red light, explain with the reason how the

State with reason why two independent sources of light cannot be considered as coherent sources.

State the criteria for the phenomenon of total internal reflection of light to take place.

How does focal length of a lens change when red colour light incident on it is replaced by violet light ? Give

Sketch the variation of intensity of interference pattern in Young’s double slit experiment.

the ratio of fringe width of bright and dark fringes in Young’s double slit experiment?

What is the effect on interference fringes in Young’s double slit experiment if one slit is covered?

A polarizer and analyzer are so oriented that intensity of transmitted light is maximum. If the analyzer is rotated

what fraction of maximum light is transmitted?

Draw a graph showing variation of intensity of polarized light transmitted by an analyzer.

soap solution appear colored in sun light. Why?

What happens to the energy at destructive interference in interference pattern?


wo polarizing sheets in the path of initially unpolarized light.

axis and that of second sheet is 60o clockwise from x-axis. Calculate what fraction of intensity of light emerges from the system. Describe two uses of total internal reflection

reflecting telescope.(cassegrain). Write two important advantages

0 cm is placed coaxially 5 cm away from a concave lens of focal length 10 cm. If an object is placed 30 cm in front of the convex lens, find the position of the final image formed by the combined system. A convex lens is placed in water. Will the focal length change? Explain. The refractive index of a material of a concave lens is n1.It is immersed in a medium of refractive

. A parallel beam of light is incident on the lens. Trace the path of ray of light when

. Three light rays red (R), green (G) and blue (B) are incident on right angled prism abc at face ab. The refractive indices of material of the prism for red, green and blue wavelengths

are respectively1.39, 1.44 and 1.47. Trace the paths of any two

A biconvex lens made of transparent material of refractive index 1.5 is immersed in water of refractive index 1.3 .Will

m of refractive index 1.65. What is the nature shown by

A glass lens of refractive index 1.5 is placed in a through of liquid. What must be the refractive index of the liquid in

is 45°, write the ratio of the intensities of original

Unpolarized light is incident on a plane surface of refractive index μ at angle i. If the reflected light gets totally

3, such that the reflected

20 cm is cut into two identical plano concave lens . What is the focal length of

laced by red light, explain with the reason how the

State with reason why two independent sources of light cannot be considered as coherent sources.

How does focal length of a lens change when red colour light incident on it is replaced by violet light ? Give

Sketch the variation of intensity of interference pattern in Young’s double slit experiment.

the ratio of fringe width of bright and dark fringes in Young’s double slit experiment?

What is the effect on interference fringes in Young’s double slit experiment if one slit is covered?

ted light is maximum. If the analyzer is rotated

Draw a graph showing variation of intensity of polarized light transmitted by an analyzer.

axis. Calculate what

(cassegrain). Write two important advantages

ay from a concave lens of focal convex lens, find the position of the final

It is immersed in a medium of refractive . A parallel beam of light is incident on the lens. Trace the path of ray of light when

rays in side and out side the prism. 8. Light of wavelength 600nm is incident on an aperture of size 2mm.Calculate the distance up to which the ray of light can travel, such that its spread is less than the size of the aperture. .9 Give statement of Huygens principle of wave front. Using it prove laws of Reflection 10. The image of candle is formed by a concave lens on a screen. The lower half of the lens is painted black to make it completely opaque .Draw the ray diagram to shoe the image formation . How will this image be different from the one obtained when the lens is not painted back. 11. Violet light is incident on a thin convex lens .If the light is replaced by a red light ,explain with reason , how the power of the lens will change 12. A convex lens of focal length 25 cm in air having refractive index of glass 1.4 is immersed in water of refractive index is 1.3. Find the apparent change in the focal length of the lens. 13. How the resolving power of a microscope is affected by increasing the aperture of the objective and by increasing the wave length of light? 14. A biconvex lens has focal length 2/3 times the radius of curvature of either surface. Calculate the refractive index of the material of the lens. 15. The refractive index of a material is √3.What is the angle of refraction if the unpolarised light is incident on it at the polarizing angle of the medium? 16. A convex lens of refractive index 1.5 has a focal length of 18 cm in air .Calculate the change in its focal length when it is immersed in water of refractive index 4/3. 17. A ray of light falls on a transparent sphere with centre C as shown in the figure. The ray emerges from the sphere parallel to the line AB. Find the angle of refraction at A if refractive index of the

material of the sphere is 3 . 18 Explain briefly how the phenomenon of the total internal reflection is used in fiber optics.

19 You are given two converging lenses of focal length 1.25cm and 5cm to design a compound microscope. if it is to

desired to have a magnification of 30, find out the separation between the objective and eyepiece.

20 . A small telescope has an objective lens of focal length 150cm and eye piece of focal length 5cm .what is magnifying

power of the telescope is for viewing distant object in normal adjustment.

21 Write the conditions for observing a rainbow .Show , by drawing suitable diagrams, to understand the formation of a

rainbow.

22A convex lens is placed in contact with a plane mirror . A point object at a distance of 20cm on the axis of this

combination has it image coinciding with itself .What is the focal length.

23 Using the lens formula show that an object placed between its optical centre and the focus of a convex lens

produces a virtual and enlarged image.

24 What type of wave front will emerge from a (i) point source, and (ii) distant light source?

25 How is the pattern in a double slit experiment related to diffraction from each slit ?

26 How does diffraction limit the resolving power of an optical instrument?

27 How does the angular separation of interference fringes change, in Young’s experiment, if the distance

between the slits is increased?

28 Two Polaroid’s P1 and P2 are 90° to each other. A third Polaroid P3 is placed between P1 and P2 bisecting the

angle between them. If the intensity of un Polaroid beam is I0 then find the intensity of transmitted beam

through P3 and P2.

29 For a ray of light travelling from a denser medium of refractive index n1 to a rarer medium of refractive index n2

, Find the critical angle for the pair of media.

30 What are coherent sources of light? State two conditions for two light sources to be coherent.

31 If a light beam shows no intensity variation when transmitted through a polaroid which is rotated, does it mean

that the light is unpolarised? Explain briefly

32 A ray is to be deviated through 90o by a right angled isosceles prism. What should be the minimum refractive

index of the material of the prism?

28 What will be the effect on interference fringes in Young’s double slit experiment if (i) Monochromatic source is

replaced by white light; (ii) Screen is moved away from the slit. Justify your answer.

29 Name one device for producing polarized light. Two polariods are placed perpendicular to each other and the

transmitted intensity is zero. What happens when one more Polaroid is placed between these two at an angle of

450?

30 In Young’s experiment the width of the fringes obtained with light of wavelength 6000 A0 is 2mm. What will be

the fringe width if the apparatus is immersed in a liquid of refractive index 4/3?

31 Show that the maximum intensity in interference pattern is four times the intensity due to each slit.

32 In a single slit diffraction experiment, the width of the slit is made double the original width. How does this

affect the size and intensity of central diffraction band?

33 How does the resolving power of a microscope change on (i) decreasing the wavelength of light (ii) decreasing

the diameter of the objective lens?

34 Draw the wavefront for a beam of light (i) coming from a convex lens when a point source is placed at its focus

(ii) divergent radially from a point source.

35 Determine the angular separation between the central maximum, and first order maximum of diffraction

pattern due to a single slit of width 0.25mm.

36 State two conditions for sustained interference of light. Draw the variation of intensity with position in Young’s

double slit experiment.

SECTION-C (THREE MARKS) 1. Using Huygens principle draw a diagram showing how plane wave gets refracted when it is incident on the surface separating a rarer medium from denser medium . Hence verify the Snell’s laws of refraction.( 2. State Huygens’s Principle of wave front. Use it to prove law of reflection of light.

3. Derive the lens formula

=

−

for a concave lens using the necessary ray diagram.

4. Draw a ray diagram to show the image formation in a refracting type astronomical telescope in the near point adjustment. Write down the expression for its magnifying power. Why should the diameter of objective of telescope be larger? 5. Two sources of intensities I and 4I are used in an interference experiment .Find the intensity at points where the waves from two sources superimpose with a phase difference (a) zero (b)π/2 . 6. How does the resolving power of a compound microscope get effected on . i) Decreasing the diameter of objective ? ii) Increasing the focal length of its objective? 7. State the conditions for sustained interference of light. In Young’s double slit experiment how the fringe width changes when (a) Separation between the slits is increased (b) Screen is moved away from the plane of the slit 8. Using Cartesian sign conventions , derive the mirror formula for a concave mirror when a real image is formed. 9. How does an un polarized light get polarized when passed through a Polaroid? Two Polaroid are set in a crossed positions. A third Polaroid is placed between the two making an angle θ with the pass axis of the first Polaroid. Write expression for the intensity of light transmitted from the second Polaroid. In what orientations will the transmitted intensity be

(i) minimum and (ii) maximum? 10. In Young's double slit experiment, monochromatic light of wavelength 630 nm illuminates the

pair of slits and produces an interference pattern in which two consecutive bright fringes are separated by 8.1 mm. Another source of monochromatic light produces the interference pattern in which the two consecutive bright fringes are separated by 7.2 mm. Find the wavelength of light from the second source. What is the effect on the interference fringes if the source is replaced by a source of white light?11. Figure shows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved a the axis until its inverted image is found at the position of the needle. The distance of the needle from the lens is measured to be 45.0 cm. The liquid is removed and the experiment is repeated. The new distance is measured to be 30.0 cm. What is the refractive index of the liquid? 12.Use the mirror equation to deduce that: an object placed between produces a real image beyond 2f. 13. A convex lens of focal length 20 cm is placed coaxially with a at a distance of 50 cm apart from each other. incident on the convex lens. Find the position of the final the ray diagram showing the formation of the image.

14. Find the ratio of intensities at two point on a screen in young’s double slit experiment when waves from the two slits have a path difference wave (i) 0 (ii) λ/4.15. Give reasons for the following :

(a) Rainbow is never observed (b) The sun looks reddish at sunrise and sunset, as viewed from earth.

16. What is the effect on linear and angular width of the interference fringes in a Young’s double experiment due to each of the following operations: (a) the screen is moved away from the plane of the slits; (b)the (monochromatic) source is repl wavelength; (c)the separation between the two slits is increased;17. A slit of width ‘a’ is illuminated by light of wavelength 700 What will be the value of slit width (i)First maximum falls at an angle of diffraction 30 (ii)First minimum falls at an angle of diffraction 3018. Consider coaxial system of two thin convex lenses of focal length f each separated by a distance d. Draw a ray diagram for image formation corresponding to an object at infinity placed on the principal axis in the following cases. (i) d< f (ii) d=f (ii)f<d<2f (iv) d=2f 19. (a) Explain clearly why the secondary maxima go on becoming weaker wit single slit diffraction . (b) When the width of the slit is made double, how would this affect the size and intensity of the 20. Consider a two slit interference arrangement (shown in figure) such that the distance of the screen from the slits is half the distance between the slits. Obtain the value of D in terms of λ such that the first minima on the screen fall at a distance D from the centre O. 21. Draw a graph showing the variation of angle of deviation ‘δ’ with that of angle of incidence ‘i’ for a monochromatic ray of light passing through a glass prism of refracting angle ‘A’. What do you interpret from the graph? Write a relation of incidence and hence derive the expression for re. Answer the following questions-

of slits and produces an interference pattern in which two consecutive bright fringes are her source of monochromatic light produces the interference pattern

in which the two consecutive bright fringes are separated by 7.2 mm. Find the wavelength of light What is the effect on the interference fringes if the monochromatic

source is replaced by a source of white light? Figure shows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved along the axis until its inverted image is found at the position of the needle. The distance of the needle from the lens is measured to be 45.0 cm. The liquid is removed and the experiment is repeated. The new distance is measured to be 30.0 cm. What is the refractive index of the liquid?

Use the mirror equation to deduce that: an object placed between f and 2f

cal length 20 cm is placed coaxially with a concave mirror of focal lengthdistance of 50 cm apart from each other. A beam of light coming parallel to principal axis is

Find the position of the final image formed by this combination.the ray diagram showing the formation of the image.

Find the ratio of intensities at two point on a screen in young’s double slit experiment when waves the two slits have a path difference wave (i) 0 (ii) λ/4.

observed on the surface of moon. (b) The sun looks reddish at sunrise and sunset, as viewed from earth.he effect on linear and angular width of the interference fringes in a Young’s double

experiment due to each of the following operations: the screen is moved away from the plane of the slits; the (monochromatic) source is replaced by another (monochromatic) source of shorter

the separation between the two slits is increased; Justify. A slit of width ‘a’ is illuminated by light of wavelength 700 nm. What will be the value of slit width ‘a’ when First maximum falls at an angle of diffraction 300? First minimum falls at an angle of diffraction 300?

Consider coaxial system of two thin convex lenses of focal length f each separated by a distance d. Draw a ray diagram for image formation corresponding to an object at infinity placed on the principal axis in the following cases. (i) d< f (ii) d=f (ii)f<d<2f (iv) d=2f Explain clearly why the secondary maxima go on becoming weaker with increasing

) When the width of the slit is made double, how would this affect the size and intensity of the central diffraction band?

Consider a two slit interference arrangement (shown in figure) such that the distance of the screen from the slits is half the distance between the slits. Obtain the

in terms of λ such that the first minima on the from the centre O.

Draw a graph showing the variation of angle of deviation ‘δ’ with that of angle of incidence ‘i’ for a monochromatic ray of light passing through a glass prism of refracting angle ‘A’. What do you interpret from the graph? Write a relation showing the dependence of angle of deviation on angle of incidence and hence derive the expression for refractive index of the prism.

of slits and produces an interference pattern in which two consecutive bright fringes are her source of monochromatic light produces the interference pattern

in which the two consecutive bright fringes are separated by 7.2 mm. Find the wavelength of light monochromatic

of a concave mirror

concave mirror of focal length 10 cm A beam of light coming parallel to principal axis is

image formed by this combination. Draw

Find the ratio of intensities at two point on a screen in young’s double slit experiment when waves

(b) The sun looks reddish at sunrise and sunset, as viewed from earth. he effect on linear and angular width of the interference fringes in a Young’s double-slit

onochromatic) source of shorter

Consider coaxial system of two thin convex lenses of focal length f each separated by a distance d. Draw a ray diagram for image formation corresponding to an object at infinity placed on the

h increasing n in

Draw a graph showing the variation of angle of deviation ‘δ’ with that of angle of incidence ‘i’ for a monochromatic ray of light passing through a glass prism of refracting angle ‘A’. What do you

showing the dependence of angle of deviation on angle fractive index of the prism.

22 In a double slit experiment using light of wave length 600nm, the angular width of the fringe formed on a distant

screen is 0.1 degree. Find the spacing between the two slits.

23.Describe Young’s double slit experiment to produce interference pattern due to a monochromatic source of light.

Deduce the expression for the fringe width.

2 4. a-Define wave front. Use Huygens principle to show diagrammatically the propagation of plane wave front from the

instant T1 =0 to the later time T2.

25- State briefly two features which can distinguish between the characteristic feature of an interference pattern from

those observed in the diffraction pattern due to a single slit.

26 A ray of light passing through an equilateral triangular glass prism from air undergoes minimum deviation

When angle of incidence is 3/4th of the angle of prism. Calculate the speed of light in the prism.

27 A convex lens of focal length 20 cm is placed coaxially with a convex mirror of radius of curvature 20 cm. The

two are kept 15 cm apart. A point object is placed 40 cm in front of the convex lens. Find the position of the

image formed by this combination. Draw the ray diagram showing the image

28 You are given three lenses L1, L2 and L3 each of focal length 10 cm. An object is kept at 15 cm in front of L1, as

shown.

The final real image is formed at the focus ‘I’ of L3. Find the separations between L1, L2 and L3.

29 A parallel beam of monochromatic light of wavelength 500 nm falls normally on a narrow slit and the resulting

diffraction pattern is obtained on a screen 1 m away. It is observed that the first minimum is at a distance of

2.5 mm from the centre of the screen. Find (a) the width of the slit. (b) the distance of the second maximum

from the centre of the screen. (c) the width of the central maximum.

30 A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a

Young’s double slit experiment. What is the least distance from the central maximum where the bright fringes

due to the both the wavelengths coincide? The distance between the slits is 2 mm and the distance between

the plane of the slits and screen is 120 cm.

31 Show, with the help of a diagram, how unpolarised sunlight gets polarized due to scattering

.

32 Trace the path of a ray of light passing through a glass prism (ABC) as shown in the

figure. If the refractive Index of glass is 3, find out of the value of the angle of

emergence from the prism.

33 Define the term 'resolving power' of an astronomical telescope. How does it get

affected on:(I )increasing the aperture of the objective lens ? (ii) increasing the

wavelength of the light used ? Justify your answer in each case.

34 A parallel beam of light of 600 nm falls on a narrow slit and the resulting diffraction

pattern is observed on a screen 1.2 m away. It is observed that the first minimum is at a distance of 3 mm

from the centre of the screen. Calculate the width of the slit.

35 Draw a labelled ray diagram of a refracting telescope. Define its magnifying power and write the expression for

it..

36 A parallel beam of light of wavelength 600 nm is incident normally on a slit of width a .If the distance between

the slit and the screen is 0.8 m and the distance of 2nd order maximum from the centre of screen is 1.5 mm,

calculate the width of slit.

37 In young’s double slit experiment using monochromatic light of wavelength λ , the intensity of light at a point

on the screen where path difference is λ ,is k units. Find out the intensity of light at a point where path

difference is λ/3.

38 Define power of a lens .Write its units. Deduce the relation

=

+

two thin lenses kept in contact

coaxially.

39 Deduce Lens Maker’s formula for a thin biconvex lens .

40 State the essential condition for Rayleigh scattering to occur. Compare the intensity of scattering of light of

wavelength 400 nm and 600 nm in the earth’s atmosphere. State the reason why the sun looks reddish at

sunset and sunrise.

41 In many experimental set-ups the source and the screen are fixed at a distance say D and the lens is movable.

Show that there are two positions for the lens for which an image is formed on screen. Find the distance

between these points and the ratio of the image sizes for these two points.

42 Derive an expression for lateral shift and normal shift. On what factors these depend.

43 Define TIR and write the conditions for TIR. Derive a relation between critical angle and the refractive index of

the medium. Also explain the working of isosceles prism and optical fiber.

44 Derive the following relation for a real image formed by a convex refracting surface when the object is placed

in rarer medium. Also write the assumptions and sign convention used. - n1/u + n2/v =

45 Derive the lens formula for concave lens.

46 .Draw a ray diagram to show the image formation in refracting type astronomical telescope in the near point

adjustment (when image is formed at LDDV i.e. D=25 cm). Derive an expression for its magnifying power. Why

the diameter of objective of telescope should be large

47 Two independent sources of light cannot be coherent. Why? Two coherent sources have intensities in the ratio

25:16. Find the ratios of the intensities of maxima to minima after interference.

48 In a single slit diffraction experiment width of the slit is made double the original width. How does it affect the

size and intensity of central diffraction band. Explain. Draw a graph showing variation of intensity with angle in

single slit diffraction.

49 When two narrow slits 2mm apart are illuminated by a light of wavelength 5000 A0 the third minima is

measured to be 0.5mm from the central maxima on a screen. What is the distance of the screen from the slit?

50 How does the resolving power of a microscope change when (i) the wavelength of the light is increased (ii) the

microscope is kept inside water (iii) diameter of the objective lens is doubled.

51 In Young’s double slit experiment when a source of light of wavelength 5000 A0 is used the fringe width

obtained is 0.6cm. If the distance between slit and screen is reduced to half what would be the wavelength of

source to get a 0.003 m wide fringes. 28. State the essential

condition for diffraction of light to occur. The light of wavelength 600nm is incident normally on a slit if width

3mm. calculate the linear width of central maximum when the screen is 3m away from the slit.

SECTION-E (FIVE MARKS) 1 (a) what the coherent source of light? State two conditions for the two light sources to be coherent (b) Derive a mathematical expression for the width of interference fringes obtained in young’s double slit experiment with the help of suitable diagram . 2.Draw a ray diagram for formation of image a point object by a thin double convex lens having radii of curvature R1 & R2. Hence derive lens maker formula for a double convex lens. State the assumption made and the sign convention used. 3. What is diffraction of light ? Draw a graph showing the variation of intensity with angle in a single slit diffraction experiment . Write one feature which distinguishes observed pattern from double slit interference pattern.

How would the diffraction pattern will be effected when (i) Width of the slit is decreased ?

(ii)The monochromatic light is replaced by source of white light? 4.Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point. In a compound microscope, an object is placed at a distance of 1 cm. If the eye piece has a focal length of 5 cm and the final image is formed at the near point, estimate the magnifying power of the microscope, 5. (a) Draw a ray diagram to show the formation of the real image of a point object due to a convex spherical refracting surface, when a ray of light is travelling from a rarer medium of refractive index µ1 to a denser medium of refractive index µ distance, image distance and radius of curvature of the spherical surface. (b) An object is placed in front of right angled prism ABC in two positions as shown. The prism is made of crown glass with critical angle of 410. Trace the path of the two rays from P & Q

6. How is the working of telescope different from that of microscope? The focal length of objective and eyepiece of a

microscope are 1.25cm and 5cm respectively. Find the po

an angular magnification of 30 in normal adjustment.

7 a-Draw a labeled ray diagram of a compound microscope, showing the formation of image at the near point of the

eye.

b-A compound microscope uses an objective lens of focal length 4cm and eye lens of focal length 10cm. An object is

placed at 6cm from the objective lens.

i- Calculate magnifying power of the compound microscope, if the final image is formed at the near point.

ii- Calculate the length of the compound microscope also.

8 Explain the phenomenon of diffraction of light at a single slit. Show graphically the variation of intensity with

angle in the diffraction pattern. What is meant by the term angular resolution of a telescope?

9 1. (a) In Young’s double slit experiment, describe briefly how bright and dark fringes are obtained on the screen

kept in front of a double slit. Hence obtain the expression for the fringe width. What is the effect on the

fringe width if the whole apparatus (YDSE) is completely immersed in a liquid of refractive index μ?

10 ) The ratio of the intensities at minima to the maxima in the Young’s double slit experiment is 9 : 25. Find the

ratio of the widths of the two slits.

11 Describe briefly how a diffraction pattern is obtained on a screen due to a single narrow slit illuminated by a

monochromatic source of light. Hence obtain the conditions for the angular width of secondary maxima and

secondary minima.

12 Two wavelengths of sodium light of 5

a single slit of aperture 2 × 10–6

m. The distance between the slit and the screen is 1.5 m. Calculate the

separation between the positions of first maxima of the diffraction

plot of intensity distribution and explain clearly why the secondary maxima become weaker with increasing

order (n) of the secondary maxima..

light is replaced by source of white light? Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point. In a compound

object is placed at a distance of 1.5 cm from the objective of focal length 1cm. If the eye piece has a focal length of 5 cm and the final image is formed at the near point,

agnifying power of the microscope,

) Draw a ray diagram to show the formation of the real image of a point object due to a convex spherical refracting surface, when a ray of light is travelling from a rarer medium of refractive

to a denser medium of refractive index µ2. Hence derive the relation between object distance, image distance and radius of curvature of the spherical surface.

(b) An object is placed in front of right angled prism ABC in two positions as shown. The prism is made of

. Trace the path of the two rays from P & Q

. How is the working of telescope different from that of microscope? The focal length of objective and eyepiece of a

microscope are 1.25cm and 5cm respectively. Find the position of the object related to the objective in order to obtain

an angular magnification of 30 in normal adjustment.

Draw a labeled ray diagram of a compound microscope, showing the formation of image at the near point of the

ope uses an objective lens of focal length 4cm and eye lens of focal length 10cm. An object is

Calculate magnifying power of the compound microscope, if the final image is formed at the near point.

the length of the compound microscope also.

Explain the phenomenon of diffraction of light at a single slit. Show graphically the variation of intensity with


1. (a) In Young’s double slit experiment, describe briefly how bright and dark fringes are obtained on the screen


hole apparatus (YDSE) is completely immersed in a liquid of refractive index μ?

) The ratio of the intensities at minima to the maxima in the Young’s double slit experiment is 9 : 25. Find the

ratio of the widths of the two slits.

how a diffraction pattern is obtained on a screen due to a single narrow slit illuminated by a


Two wavelengths of sodium light of 590 nm and 596 nm are used in turn to study the diffraction taking place at


separation between the positions of first maxima of the diffraction pattern obtained in the two cases. Draw a


order (n) of the secondary maxima..

Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point. In a compound

5 cm from the objective of focal length 1. 25 cm. If the eye piece has a focal length of 5 cm and the final image is formed at the near point,

) Draw a ray diagram to show the formation of the real image of a point object due to a convex spherical refracting surface, when a ray of light is travelling from a rarer medium of refractive

. Hence derive the relation between object

. How is the working of telescope different from that of microscope? The focal length of objective and eyepiece of a

sition of the object related to the objective in order to obtain

Draw a labeled ray diagram of a compound microscope, showing the formation of image at the near point of the

ope uses an objective lens of focal length 4cm and eye lens of focal length 10cm. An object is

Calculate magnifying power of the compound microscope, if the final image is formed at the near point.

Explain the phenomenon of diffraction of light at a single slit. Show graphically the variation of intensity with


1. (a) In Young’s double slit experiment, describe briefly how bright and dark fringes are obtained on the screen


hole apparatus (YDSE) is completely immersed in a liquid of refractive index μ?

) The ratio of the intensities at minima to the maxima in the Young’s double slit experiment is 9 : 25. Find the

how a diffraction pattern is obtained on a screen due to a single narrow slit illuminated by a


90 nm and 596 nm are used in turn to study the diffraction taking place at


pattern obtained in the two cases. Draw a


UNIT-VII (DUAL NATURE)

1. define work function for a given metallic surface? 2. On what principle an electron microscope is based? 3. Write an expression for the de Broglie wavelength associated with a charged particle having charge 'q' and mass' m' when it is accelerated by a potential V. 4. Define threshold wavelength for Photoelectric effect. 5.How does de Broglie wavelength depend on the momentum of a particle? Define the term Threshold Frequency in relation to photoelectric effect.

7Name an experiment which shows wave nature of electrons. Which phenomenon was observed in this experiment

using an electron beam?

8 With what purpose was famous Davisson-Germer experiment with electrons performed?

9. An electron and alpha particle have the same kinetic energy. How is the de Broglie wavelength associated with them

related?

10. Show graphically how the stopping potential for a given photosensitive surface varies with the frequency of incident

radiations.


1. In photoelectric effect, why should the photoelectric current increase as the intensity of monochromatic radiation incident on a photosensitive surface is increased? Explain 2. Plot a graph showing variation of photoelectric current with collector plate potential at a given frequency and intensity of incident radiation. What does the intercept of the graph with potential axis signify? 3. Plot a graph showing the variation of photoelectric current with collector plate potential at a given frequency but for two different intensities I 1 and I 2 , where I 2 > I 1. 4. Define intensity of radiation on the basis of photon picture of light. Write its SI unit. 5. A monochromatic light source of power 5mW emits 8X1015 photons per second. This light ejects photoelectrons from a metal surface. The stopping potential for this set up is 2V. Calculate the work function of the metal. 6. The graph shows the variation of stopping potential with frequency of incident radiation for two photosensitive metals A and B. Which one of the two has higher value of work-function? Justify . 7. A proton and a deuteron are accelerated through the same accelerating potential. Which one of the two has (i) greater value of de-Broglie wavelength associated with it, and(ii) less momentum? Give reasons to justify your answer.

8. (i) Monochromatic light of frequency 6.0 × 1014 Hz is produced by a laser. The power emitted is 2.0 × 10–3 W. Estimate the number of photons emitted per second on an average by the source. (ii) Draw a plot showing the variation of photoelectric current versus the intensity of incident radiation on a photosensitive surface. 9. Ultraviolet light of wavelength 2271 Ao from 100 W mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is –1.3 V, estimate the work function of the metal. How would the photocell respond when the source is replaced by another source of high intensity (~10 5Wm -2 ) red light of wavelength 6328 Ao Justify your answer. 10. An electron and a proton, each have de Broglie wavelength of 1.00 nm. (a) Find the ratio of their moment. (b) Compare the kinetic energy of the proton with that of the electron. 11. Write the expression for the de Broglie wavelength associated with a charged particle having charge’s’ and mass ‘m’, when it is accelerated by a potential V. 12. Write Einstein’s photoelectric equation and point out any two characteristic properties of photons on which this equation is based. Briefly explain the three observed features which can be explained by this equation. 13. The given graph shows the variation of photo-electric current (I) versus applied voltage (V) for two different photosensitive materials and for two different intensities of the incident radiation. Identify the pairs of curves that correspond to different materials but same intensity radiation. 14. Write the basic features of photon picture of electromagnetic radiation on which Einstein’s photoelectric equation is based. 15. Show graphically how the stopping potential for a given photosensitive surface varies with the frequency of incident radiations.

16 An alpha particle and a proton are accelerated from rest by the same potential. Find the ratio of their de-Broglie

wavelength.

17 Light of wavelength 2500A0 falls on a metal surface of work function 3.5 e v. What is the K.E of (i) Fastest and (ii)

slowest electron from the surface emitted.

18 What is maximum kinetic energy of a photoelectron whose Work functions is 2.5 e v if a radiation of 5.2 e v

incident on it?

19 Two metals A and B have work function 2 e V and 5 e V respectively .which metal has lower threshold wave

length?

20 A proton and an electron have same de-Broglie wavelength which of them moves fast and which possesses

more K.E. Justify your answer

21 Sketch a graph between frequency of incident radiations and stopping potential for a given photosensitive

material. What information can be obtained from the intercept on the potential axis?

22 An electron and a proton are accelerated through the same potential. Which one and the two has greater value

of de-Broglie wavelength associated with it and (ii) less momentum? Justify your answer.

23 Point out the two curves for which the incident radiations have same frequency but different intensities.

24 A deuteron and proton have same KE. Which of these particles has the shortest de-Broglie wavelength?

25 Work function of Sodium is 2.3 e V. Does Sodium show photoelectric emission for light of wavelength 6800A0?

26 Electrons are emitted from a photosensitive material when it is illuminated by green light but electron emission

does not take place by yellow light. Will the electrons be emitted when the surface is illuminated by (i) Red (ii)

Blue light? Explain.

27 Ultraviolet radiations of different frequencies ν1 and ν2 are incident on two photosensitive materials having

work functions Ф1 and Ф2 (Ф1>Ф2) respectively. The KE of the emitted photoelectrons are same in both

cases. Which of the two will be of higher frequency?

28 Write Eienstein 's Photoelectric equation and point out any two characteristics properties of photons on which this equation is based?

29 . When the electron orbiting in hydrogen atom in its ground state moves to the third excited state, show how the de Broglie wavelength associated with it be affected?

30 A beam of monochromatic radiation is incident on a photosensitive surface .Answer the following questions giving reasons :

31 i)Do the emitted photoelectrons have the same kinetic energy?

ii) does the kinetic energy of the emitted electrons depend on the intensity of incident radiation iii)On what factors does the number of emitted photoelectrons depend?

32 The photoelectric cut -off voltage in a certain photoelectric experiment is 1.5 volt. What is the maximum kinetic energy of electrone.

SECTION-C (THREE MARKS) 1 An electromagnetic wave of wavelength l is incident on a photosensitive surface of negligible work function. If the photo-electrons emitted from this surface have the de-Broglie wavelength l1, prove that λ=2mcλ12/h 3. (a) Describe briefly how Davisson – Germer experiment demonstrated the wave nature of electrons.(b) An electron is accelerated from rest through a potential V. Obtain the expression for the de- Broglie wavelength associated with it. 4. Compare the photoelectric effect on the basis of photon theory and wave theory of light and hence explain why the wave theory failed to explain it. 5 Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two

different photosensitive materials having work functions W1 and W2 (W1 > W2 ). On what factors does the

slope and (ii) intercept of the lines depend? 6 The work function of cesium metal is 2.14 e V. When light of frequency 6 x 1014 Hz is incident on the metal

surface, photoemission of electrons occurs. What is the (a) maximum KE of the emitted photoelectrons (b)

Stopping potential and (c) Maximum speed of emitted photoelectrons?

7 Write two characteristic features observed in photoelectric effect which do not support the wave picture of

electromagnetic radiation.

8 Draw a graph between the frequency of incident radiation (v) and the maximum kinetic energy of the electrons

emitted from the surface of a photosensitive material. State clearly how this graph can be used to determine

(i) Plank’s constant and (ii) work function of the material.

9 In a plot of photoelectric current versus anode potential, how does (i) the saturation current vary with anode

potential for incident radiations of different frequencies but same intensity? (ii) the stopping potential vary for

incident radiations of different intensities but same frequency?(iii) Photoelectric current vary for different

intensities but same frequency of incident radiations? Justify your answer.

10 Write Einstein’s photoelectric equation and point out any two characteristic properties of photons on which this

equation is based.

11 . How did de Broglie hypothesis lead to Bohr's quantum condition of atomic orbits? 12 Monochromatic light of frequency 6 x10 14 is produced by a laser. The power emitted is 2x 10-3 W.How many photons per second on an average are emitted by the source?

13 Derive Einstein’s Photoelectric equation. 14 . Describe Davisson and Germer's experiment to demonstrate the wave nature of electrons. Draw a labeled diagram of apparatus used

UNIT-VIII (ATOMS & NUCLEI) SECTION-A (ONE MARK)

1. In both β+, β- decay processes, the mass number of a nucleus remains same whereas the atomic number Z increases by one in β-decay and decreases by one in β+ decay. Explain, giving reason. 2. Why is it found experimentally difficult to detect neutrinos in nuclear β-decay? 3. What is the nuclear radius of 56Fe, if that of 27Al is 3.6 fermi? 4. Two nuclei have mass numbers in the ratio 2 : 5. What is the ratio of their nuclear densities? 5. In the Rutherford scattering experiment the distance of closest approach for an a-particle is

d0.If a-particle is replaced by a proton, how much kinetic energy in comparison to a-particle will it require to have the same distance of closest approach d0? 6. What is the ratio of radii of the orbits corresponding to first excited state and ground state in a hydrogen atom?

7 How will the distance of closest approach change when(i) the K.E. of the projectile is doubled (ii) velocity of the

projectile is halved ?

8 Define the activity of a given radioactive substance. Write its S.I. unit.

9 Find out the ratio of nuclear densities of O816

to Fe 2656

.

10 Write any two charteristics properties of nuclear force.

11 How is the mean life of a radioactive sample related to its half life ?

12 What is the significance of negative energy of electron in an orbit ?

13 Write the expression for Bohr’s radius in hydrogen atom .

14 Draw a plot of potential energy of a pair of nucleons as a function of their separation. Write two important

conclusions. Which you can draw regarding the nature of nuclear forces?

15 With the help of an example explain how the neutron to proton ratio changes during alpha decay of a nucleus .

16 If the nucleons bound in a nucleus are separated apart from each other , the sum of their masses is greater than

the mass of the nucleus. Where does this difference come from ? Explain briefly .

17 How is the mean life of radioactive sample related to its half-life?

18 Write expression for Bohr’s a radius in hydrogen atom.

19 Define the term activity of a radionuclide? Write its S,I unit.

20 Write any one equation representing nuclear fusion reaction.


1.The energy of the electron in the ground state of hydrogen atom is - 13 . 6 eV . (i) What does the negative sign signify? (ii) How much energy is required to take an electron in this atom from the ground state to the first excited state? 2. The following table shows some measurements of the decay rate of a radionuclide sample. Find the disintegration constant.

Time (min) lnR (Bq) 36 5.08 100 3.29 164 1.52 218 1.00

3. A radioactive nucleus ‘A’ undergoes a series of decays according to the following scheme : 4321 AAAAA →→→→ γαβα

The mass number and atomic number of A are 190 and 75

respectively. What are these numbers for A4 ? 4. The half life of a radioactive substance is 30 s. Calculate (i) the decay constant, and (ii) time taken for the sample to decay by 3/4th of the initial value. 5.A heavy nucleus X of mass number 240 and binding energy per nucleon 7.6 MeV is split into two fragments Y and Z of mass numbers 110 and 130. The binding energy of nucleons in Y and Z is 8.5 MeV per nucleon. Calculate the energy Q released per fission in MeV. 6 The energy of the electron in the ground state of hydrogen atom is – 13. 6 eV .How much energy is required to take

an electron in this atom from the ground state to the first excited state? 7 Define 1a.m.u? What is its relation with kilogram?

8 Differentiate between isotones and isobars?

9 Define mass defect and binding energy of nucleus? With binding energy curve in mind, show that why is

uranium so unstable.

9 The activity of a radioactive material drops to 1/14 th of its value in 24 hours. Calculate the half-life and the

decay constant?

10 Is the mass of electrons obtained by all sources equal?

11 The mass of β-particle is higher than the mass of electrons obtained by other sources, where as β-particles are

also electrons.

12 What do you mean by the half life of a radioactive element? Explain half life time and decay constant by drawing

a curve between un disintegrated atoms of the element and time?

13 After a certain lapse of time, the fraction of radioactive polonium un decayed is found to be 4.625% of its initial

quantity. What is the duration of this time lapse if the half life of polonium is 138 days?

14 Differentiate between the units Becquerel and curie?

15 . How long an electric lamp of 100 W can be kept glowing by fusion of 2.0 kg of deuterium ? The fusion reaction can be taken as 1H2+1H2---2He3+n+3.2MeV

16 . Calculate the shortest wavelength in the Balmer series of hydrogen atom .In which region (infra -red ,visible, ultraviolet ) of hydrogen spectrum does this wavelength lie

17 3. Define half life and mean life of a radioactive sample. 18 4. Distinguish between nuclear fission and radioactive decay.


1. State the law of radioactive decay. If N0 is the number of radioactive nuclei in the sample at some initial time, t 0 , find out the relation to determine the number N present at a subsequent time. Draw a plot of N as a function of time. 2. Draw a plot of the binding energy per nucleon as a function of mass number for a large number of nuclei. Explain the energy release in the process of nuclear fission from the above plot. Write a typical nuclear reaction in which a large amount of energy is released in the process of nuclear fission. 3. Identify the type of waves which are produced by the following way and write one application for each: (i) Radioactive decay of the nucleus, (ii) Rapid acceleration and decelerations of electrons in aerials, (iii) Bombarding a metal target by high energy electrons. 5. (i) Define ‘activity’ of a radioactive material and write its S.I. unit. (ii) Plot a graph showing variation of activity of a given radioactive sample with time. (iii) The sequence of stepwise decay of a radioactive nucleus is

21 DDD →→−βα

If the atomic number and mass number of D2 are 71 and 176 respectively, what are their corresponding values for D ? 4. The energy level diagram of an element is given below. Identify, by doing necessary calculations, which transition corresponds to the emission of a spectral line of wavelength 102.7 nm. 5A radioactive nucleus ‘A’ undergoes a series of decays according to the following scheme :

6 The mass number and atomic number of A are 180 and 72 respectively. What are these numbers for A 4 ?

7 In an experiment on alpha particle scattering by a thin foil of gold, draw a plot showing the number of particles

scattered versus the scattering angle Ф. Why is it that a very small fraction of the particles are scattered a

900? Write two important conclusions that can be drawn regarding the structure of the atom from the study

of this experiment.

8 Derive the expression for the law of radioactive

the number N present at any subsequent time t. Plot a graph showing the variation of the number of n

versus the time t lapsed.Mark a point on the plot in terms of T 1/ 2 value wh

9 A nucleus Ne23

10 undergoes β- decay and becomes

10 Calculate the maximum kinetic energy of electrons emitted

assuming that the daughter nucleus and anti

negligible kinetic energy

11 The half life of C-12 is 5700 years. What does it mean? Two radioactive nuclei P and Q initially contain an equal

number of atoms. Their half life is 1 hour and 2 hours respectively. Calculate the ratio of their rates of

disintegration after two hours.

12 Using the curve for the binding energy per nucleon as a function of mass number A, state clearly how the

release in energy in the processes of nuclear fission and nuclear fusion can be explained.

13 Derive an expression for radius and Tot

model.

14 Draw the plot of binding energy per nucleon (BE/A) as a function of mass number A. Write two important

conclusions that can be drawn regarding the nature of nuclear force?

Use this graph to explain the release of energy in both the processes of nuclear fission and fusion?

15 Calculate the energy released in Mev in the following nuclear reaction

92 U 238 90 Th 234 + 2 He 4 +Q Mass of

=4.002600u 1u=931.5 Mev

16 Draw a Schematic arrangement of the Geiger

a thin foil of gold provide an important way to determine an upper limit on the size of

17 Using Bohr’s postulates for hydrogen atom, show that the total energy (E) of the electron in the stationary states

can be expressed as the sum of kinetic energy (K) and potential energy(U) , where U=

18 Define the term decay constant and half

How many disintegrations per second will occur in one gram of 92 U 238 , if its half

1.42x10 17

s ?

19 A star converts all its hydrogen to helium achieving 100% helium composition. It then converts helium to carbon

via the reaction:

2He4 →6 C

12 + 7.27 MeV

The mass of the star is 5.0 x 1030

kg and it generates energy at the rate of

all its helium to carbon?

20 The ground state energy of hydrogen atom is

0.85ev to -3.4 ev , calculate the wave length of the spectral

wave length belong.

21. Draw plot of potential energy of pair of nucleon as function of their separations. Mark the region s where the

nuclear force is (i) attractive and (ii) repulsive .Write any

22. Using the postulates of Bohr’s model of hydrogen atom , obtain expression for the frequency of radiation emitted

when the atom makes a transitions from the higher energy state with quantum number n

with quantum number nf. .(ni<nf)

23 . Why is the mass of the nucleus always less than the sum of the masses of its constituents , neutrons and protns ? If

the total number of neutron and protons in a nuclear reaction is conserved ,

in the reaction .Explain .

In an experiment on alpha particle scattering by a thin foil of gold, draw a plot showing the number of particles

scattered versus the scattering angle Ф. Why is it that a very small fraction of the particles are scattered a


Derive the expression for the law of radioactive decay of a given sample having initially N0 nuclei decaying to

the number N present at any subsequent time t. Plot a graph showing the variation of the number of n

Mark a point on the plot in terms of T 1/ 2 value when the number present N = N0 /16

decay and becomes Na23

11 .

Calculate the maximum kinetic energy of electrons emitted

assuming that the daughter nucleus and anti-neutrino carry

is 5700 years. What does it mean? Two radioactive nuclei P and Q initially contain an equal


Using the curve for the binding energy per nucleon as a function of mass number A, state clearly how the


Derive an expression for radius and Total Energy of electron in the nth orbit of Hydrogen atom in Bohr atomic

Draw the plot of binding energy per nucleon (BE/A) as a function of mass number A. Write two important

conclusions that can be drawn regarding the nature of nuclear force?


Calculate the energy released in Mev in the following nuclear reaction

90 Th 234 + 2 He 4 +Q Mass of 92 U 238 =238.05079 u, 90 Th 234

Draw a Schematic arrangement of the Geiger-Marsden experiment. How did the scattering of alpha particles by

a thin foil of gold provide an important way to determine an upper limit on the size of

Using Bohr’s postulates for hydrogen atom, show that the total energy (E) of the electron in the stationary states

can be expressed as the sum of kinetic energy (K) and potential energy(U) , where U=

onstant and half-life of a radioactive sample. Derive the relation connecting the two.

How many disintegrations per second will occur in one gram of 92 U 238 , if its half

helium achieving 100% helium composition. It then converts helium to carbon

+ 7.27 MeV

kg and it generates energy at the rate of 5 x 1030

watt. How long will it take to convert

The ground state energy of hydrogen atom is -13.6 ev . If an electron makes an transition from an energy level

3.4 ev , calculate the wave length of the spectral line emitted . two which series hydrogen spectrum does this

. Draw plot of potential energy of pair of nucleon as function of their separations. Mark the region s where the

nuclear force is (i) attractive and (ii) repulsive .Write any two characteristics feature of nuclear forces .

. Using the postulates of Bohr’s model of hydrogen atom , obtain expression for the frequency of radiation emitted

when the atom makes a transitions from the higher energy state with quantum number nitwo t

. Why is the mass of the nucleus always less than the sum of the masses of its constituents , neutrons and protns ? If

the total number of neutron and protons in a nuclear reaction is conserved , hoe then is the energy absorbed or evolved

In an experiment on alpha particle scattering by a thin foil of gold, draw a plot showing the number of particles

scattered versus the scattering angle Ф. Why is it that a very small fraction of the particles are scattered at Ф>


decay of a given sample having initially N0 nuclei decaying to

the number N present at any subsequent time t. Plot a graph showing the variation of the number of nuclei

the number present N = N0 /16.

is 5700 years. What does it mean? Two radioactive nuclei P and Q initially contain an equal


Using the curve for the binding energy per nucleon as a function of mass number A, state clearly how the


al Energy of electron in the nth orbit of Hydrogen atom in Bohr atomic

Draw the plot of binding energy per nucleon (BE/A) as a function of mass number A. Write two important


92 U 238 =238.05079 u, 90 Th 234 =234.043630 u, 2 He 4

Marsden experiment. How did the scattering of alpha particles by

a thin foil of gold provide an important way to determine an upper limit on the size of the nucleus ?

Using Bohr’s postulates for hydrogen atom, show that the total energy (E) of the electron in the stationary states

can be expressed as the sum of kinetic energy (K) and potential energy(U) , where U= -2K.

life of a radioactive sample. Derive the relation connecting the two.

How many disintegrations per second will occur in one gram of 92 U 238 , if its half-life against alpha decay is

helium achieving 100% helium composition. It then converts helium to carbon

watt. How long will it take to convert

13.6 ev . If an electron makes an transition from an energy level -

line emitted . two which series hydrogen spectrum does this

. Draw plot of potential energy of pair of nucleon as function of their separations. Mark the region s where the

two characteristics feature of nuclear forces .

. Using the postulates of Bohr’s model of hydrogen atom , obtain expression for the frequency of radiation emitted

two the lower energy state

. Why is the mass of the nucleus always less than the sum of the masses of its constituents , neutrons and protns ? If

hoe then is the energy absorbed or evolved

SECTION-D (FOUR MARKS) 1. For the past some time, Aarti had been observing some erratic body movement, unsteadiness and lack of coordination in the activities of her sister Radha, who also used to complain of severe headache occasionally. Aarti suggested to her parents to get a medical check-up of Radha. The doctor thoroughly examined Radha and diagnosed that she has a brain tumour. (a) What, according to you, are the values displayed by Aarti? (b) How can radioisotopes help a doctor to diagnose brain tumour?

. For the past some time, Aarti had been observing some erratic body movement, unsteadiness and lack of

coordination in the activities of her sister Radha, who also used to complain of severe headache occasionally.

Aarti suggested to her parents to get a medical check-up of Radha. The doctor thoroughly examined Radha

and diagnosed that she has a brain tumour.

(a) What, according to you, are the values displayed by Aarti?

(b) How can radioisotopes help a doctor to diagnose brain tumour?

2. Muthuswami a resident of Kundakulam was all set to leave everything and shift to another place in view of the

decision of Govt. to start nuclear thermal power plant at Kundakulam. His granddaughter Prachi, a science

student, was really upset on the ignorant decision of her grandfather. She could finally convince him not to shift,

since adequate safety measures to avoid any nuclear mishap have already been taken by the Govt. before

starting nuclear thermal plants.

• What is the value displayed by Prachi in convincing her grandfather ?

• What is the principle behind working of nuclear reactor ?

• What are the main components of nuclear reactor ?

• Why is heavy water used as moderator?

SECTION-E (FIVE MARKS) 1. (a) Define the terms (i) half-life (T1/2) and (ii) average life (τ). Find out their relationships with the decay constant (λ). (b) A radioactive nucleus has a decay constant 0.3465 (day)–1. How long would it take the nucleus to decay to 75% of its initial amount?

Using Bohr’s postulates, derive the expression for the frequency of radiation emitted when electron in hydrogen

atom undergoestransition from higher energy state (quantum number ni) to the lower state, (nf).When

electron in hydrogen atom jumps from energystate ni = 4 to nf = 3, 2, 1, identify the spectral series to which

the emission lines belong.

2.(a) Use binding energy per nucleon (BE/A) graph to explain the release of energy in both the processes of nuclear

fusion and fission.(b) Write the basic nuclear process of neutron undergoing β-decay.

Why is the detection of neutrinos found very difficult?

3. State Bohr's postulates of atomic model. Using this derive the expression for radius, velocity and energy of

electron revolving in nth orbit

UNIT-IX (SEMICONDUCTOR) 1. What happens to the width of depletion player of a p-n junction when it is (i) forward biased, (ii) reverse

biased?

2. What is LDR? How it is used for measurement of Intensity of light.

3. Draw a voltage –current characteristic of a zener diode .

4. Why should a photo diode be operated at a reverse bias ?

5. Name one impurity each , which when added to pure Si, produces (i) n-type and (ii) p-type semiconductor.

6. Give the logic symbol of AND gate.

7. .Why should a photodiode be operated at reverse bias?

8. . Give logic symbol of NAND gate.

9. . Draw energy band diagram of p-type semiconductor.

10. Name the type of biasing of p-n junction diode so that junction offers very high resistance.

11. . Give logic symbol of NOR gate

12. How is a n-p-n transistor represented symbolically?

13 How does conductivity of a semiconductor change with temperature?

14 Draw energy band diagram for a p-type extrinsic semiconductor.

15 Give the ratio of number of holes and the number of conduction electrons in an intrinsic semiconductor?

16 What is the order of energy gap in the semiconductor?

17 In the figure given below, state the type of biasing of the diode.

18 Which gate is represented by the symbol shown?

19 Frequency of input voltage to a half wave rectifier is 50 Hz. What will be the frequency of output

voltage?

20 Name the type of charge cariers in p-n junction diode when forward biased. 2.1 what signal voltage is represented for positive logic state 1 ? 22 what is the frequency of output signal of i)half wave rectifier ii) full wave rectifier the frequency input signal is 50 hz?

23 how does one understand the temperature dependence of resistivity is Semi conductor?

24 . state with reason why a photodiode is usually operated at a reverse bias. 25 The energy gaps is the energy band diagrams of a conductor semiconductor and insulator are E1 E2 and E3 arrange them in increasing order.

26 Define transconductance of a transistor

SECTION-B (TWO MARKS) 1. In the figure given below, the input waveform is converted into the output wave from a device ‘X’. Name the device and draw its circuit diagram. 2. Distinguish between an intrinsic semiconductor and P-type semiconductor. Give 3. Explain the formation of depletion layer and potential barrier in a p-n junction.

4. A logic gate is obtained by applying output of AND gate to a NOT gate. Name the gate so formed. Write the symbol and truth table of this gate. 5. Explain, with the help of a circuit diagram, the working of a p-n junction diode as a half-wave rectifier. 6. Draw a circuit diagram of n-p-n transistor amplifier in CE configuration. Under what condition does the transistor act as an amplifier? 7 Name the semiconductor device that can be used to regulate an unregulated dc power supply. With the help of I-V

characteristics of this device, explain its working principle.

8 Draw the circuit diagram of an illuminated photodiode In reverse bias. How is photodiode used to measure light

intensity?

9 A logic gate is obtained by applying output of AND gate to a NOT

gate. Name the gate so formed. Write the symbol and truth table

of this gate.

10 Draw a circuit diagram showing the biasing of an LED.

11 State the factor which controls

a. Wavelength of light

b. Intensity of light emitted by the diode.

12 C, Si and Ge have the same lattice structure.

13 Why is C insulator while Si and Ge intrinsic semiconductor

14 Draw the output wave form at X, using the given inputs A, B

for the logic circuit shown below. Also identify the gate.

15 Distinguish between an intrinsic semiconductor and P-type semiconductor. Give reason, why a P-type

semiconductor crystal is electrically neutral, although nh >> ne?

16 Write any two distinguishing features between conductors, semiconductors and insulators on the basis of

energy band diagrams.

17 .Descibe the briefly whit the help of a circuit diagram , the paths of current carriers in an n-p-n transistor with emitter

–base junction forward biased and base collector junction reverse biased.

18 Write two characteristic features to distinguish between n-type and p-type semiconductor.

19 If the output of two input NOR gate fed as both input A and B two another NOR gate ,Write down a truth table to

find the final output for all combinations of A and B.

20Show the biasing of a photodiode with the help of a circuit diagram .Draw the graphs to show variations in reverse

bias currents for different illuminations intensities.

20 What is potential barrier? How does the thickness of the depletion region in a p-n junction diode

change, if it is forward biased?

21 The output of an OR gate is connected to both the inputs of a NAND gate, draw the logic circuit of the

combination of gates and write its truth table.

22 What is a light emitting diode (LED)? Mention two important advantages of LEDs over conventional

camps

23 For a transistor Ic/ =0.96.Calculate the current gain in CE configuration.

24 What is an ideal diode? Draw the output wave form across R for the input wave form given below.

25 Draw the energy band diagram to distinguish between insulators, conductors and semiconductors.

26 With the help of a circuit diagram explain the use of Zener diode as voltage stabilizer.

27 The input resistance of a common emitter amplifier is 2 kΩ and a.c. current gain is 20. If the load

resistor used 5 kΩ. Calculate (i) the voltage gain (ii) transconductance.

29 Identify the logic gate marked, X, Y. Write down the output at y ,when A=0, B=1 AND A=1 B=0,

30 A photo diode is fabricated from a semiconductor with band gap of 2.8 eV. Can it detect a wave length

of 6000 nm? Justify.

31 Draw a circuit diagram for a pn-junction diode in forward and reverse bias. Sketch the V-I graphs for

them.


1. Write any two distinguishing features between conductors, semiconductors and insulators on the basis of energy band diagrams. 2. Explain the following: (i) In the active state of the transistor, the emitter base junction acts as a low resistance while base collector region acts as high resistance. (ii) Output characteristics are controlled by the input characteristics in common emitter transistor amplifier. (iii) LEDs are made of compound semiconductor and not by elemental semiconductors.

3.The graph of potential barrier versus width of depletion region for an unbiased diode is shown in A. In comparison to A, graphs B and C are obtained after biasing the diode in different ways. Identify the type of biasing in B & C and

justify your answer.

4. Distinguish between a metal and an insulator on the basis of energy band diagrams. 5. (a) Why is zener diode fabricated by heavily doping both p-and n-sides of the junction? (b) Draw the circuit diagram of zener diode as a voltage regulator and briefly explain its working. 6. (a) How is photodiode fabricated? (b) Briefly explain its working. Draw its V–I characteristics for two different intensities of illumination. 7. The given inputs A, B are fed to a 2-input NAND gate.

Draw the output wave form of the gate.

8. Draw a circuit diagram of an n-p-n transistor with its emitter base junction forward biased

and base collector junction reverse biased. Describe briefly its working. Explain how a transistor in active state exhibits a low resistance at its emitter base junction and high resistance at its base collector junction. 9. With the help of a labelled circuit diagram explain the use of a p-n junction diode as a full wave rectifier. Draw the input and output waveforms. 10. Identify the equivalent gate represented by the circuit shown in the figure. Draw its logic symbol and write the truth table. 11. Draw energy band diagrams of an n-type and p-type semiconductor at temperature T > 0 K. Mark the donor and acceptor energy levels with their energies.

11 Draw a labeled diagram of a full wave rectifier circuit. State its working principle. Show the input- output

waveforms.

12 Name the important processes that occur during the formation of a p-n junction. Explain briefly, with the help

of a suitable diagram, how a p-n junction is formed. Define the term ‘barrier potential’.

13 With a circuit diagram, briefly explain how a zener diode can be used as a voltage regulator.

14 For a CE- transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2V. Suppose the

current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base

resistance is 1 kΩ.

15 What is LED? Mention two important advantages of LEDs over conventional lamps.

16 What are extrinsic semiconductors? Mention its types and explain the mechanism of conduction in each.

17 Explain the conduction in N Type and P Type semiconductor on the basis of band theory.

18 Explain how the fundamental logic gates can be realised using NAND gates alone.

19 With the help of a labeled circuit diagram explain the working of half wave rectifier and draw the input and

output waveforms.

20 Explain the action of a PNP transistor and an NPN transistor.(Explain how conduction takes place in NPN and

PNP transistor.)

21 Draw the circuit diagram for determining transistor characteristics and describe the input and output

characteristics of transistor in CE configuration with relevant graphs.

22 Draw the symbol, truth table and Boolean expression for OR, AND and NOT gate.

23 Draw the symbol and truth table of NOR gate and NAND gate.

24 Explain, how the fundamental logic gates can be realized using NOR gates alone.

25 On the basis of the energy band diagram distinguish between metals, insulators and semiconductors.

26 What is an intrinsic semiconductor? How can this material be converted (i) p- type semiconductor (ii) n- type

semiconductor? Explain with help of energy band diagram.

27 Describe the working of light emitting diode (LED) (ii) What semiconductors are preferred to make LED diode

(i) Give two advantages of using LED over conventional incandescent low power lamps.

28 Explain with neat diagram formation of energy bands in solids. Define conduction band and valance

band.

29 What is an intrinsic semiconductor? How can this material be converted in to p-type and n-type

semiconductor? Explain with electron bond diagram.

30A transistor is used in common emitter mode in an amplifier circuit. When a signal of 24 mV is added to the

base emitter voltage, the base current changes by 32µA and collector current by 3.6 mA. The load resistance is

4.5 kΩ. Calculate (i) the current gain β (ii) the input resistance (iii) the transconductance !(iv) the voltage

gain ".

32 Why NAND gate is called universal gate? Draw the diagram to convert NAND gate alone in to OR

gate

Or

Using only NOR gate how to obtained (i) AND gate (ii) OR gate

33 A semiconductor has an equal electron and hole concentration of 6 x10% /&'

.On doping with certain

impurity, electron concentration increases to 4x 10 )/&'.

(i) What type of semiconductor is obtained on doping?

(ii) Calculate the new electron and hole concentration of the semiconductor.

(iii) How does the energy gap vary with doping?

34 What is the need of rectification? With the help of circuit diagram, explain the working of half wave

rectifier. Draw its input and output wave forms.

The ratio of the number density, of free electrons to holes,* /*+ , for three different materials A, B and C are

equal to one, less than one more than one respectively. Name the type of semiconductor to which A, B and C

belong. Draw labeled energy band diagrams for the three materials

5 MARKS QUESTIONS

1. explain the formation of the depletion reason for a p-n junction how does the width ok this season reason is change when the junction i) forward biased ii) reversed biased and iii) how does an increase in the doping concentration and set the width of the depletion region? 2. a) draw the circuit diagram of p-n Junction diode in forward bias reverse bias how are the circuits used to study the V-I characteristic of a silicon dad draw the typing V-I characteristics. b) what is light emitting diode mention two important advantages of LED over conventional lamps 3. describe briefly with the help of a diagram the role of the two important processes involved in the formation of a p-n Junction. b) name the device which is used as a voltage regulator draw the necessary circuit diagram and explain its working. 4. how is zener diode fabricated so as to make it special purpose diode? draw I-V characteristics of zener diode and explain the significance ofbreakdownvoltage explain

briefly with the help of a circuit diagram how a p-n junction diode works as a half wave rectifier. 5.a) draw the circuit arrangement for studying the input and output characteristics of an n-p-n transistor in CE configuration with the help of these characteristics define input resistance current amplification factor. b) explain with the help of a circuit diagram working of NPN transistor is it common emitter amplifier. 6 . Draw the circuit diagram to study the characteristic of npn transistor in common emitter configuration.

Sketch typical (i) input characteristics (ii) output characteristics for such a configuration. Explain how the

current gain of transistor is calculated from output characteristics.

7 Draw the circuit diagram and transfer characteristics of a base biased transistor in common emitter

configuration. Explain briefly the meaning of cut off, active and saturation region. Referring to the diagram

explain transistor as a switch.

8 State and define various basic gates. Draw the logic symbols and write the truth table for them. Explain how

will you obtain NOR gate and NAND gate from them. For a binary signal 1101001, draw the wave form and

output wave form for NOT gate.

UNIT-X (COMMUNICATION) ONE MARK

1. What is meant by transducer? Give one example of a transducer.

2. What is the function of a ‘Repeater’ in a communication system?

3. Why should transmitters broadcasting programmes use different carrier frequencies?

4. Give expression for bandwidth in FM modulation.

5. Define modulation index.

6. Why is the amplitude of modulating signal kept less than the amplitude of the carrier wave ?

7. What is space wave communication? Write the range of frequencies suitable for space wave communication.

8. What is the range of frequencies used in satellite communication? What is common between these waves and

light waves?

9. What is communication system ? Describe briefly the major constituents of a communication system.

10. What is the role of band pass filter in amplitude modulation?

11.

12. What are the three basic units of a communication system?

13. Identify the parts X and Y in the following block diagram of a generalized communication system?

14. Name two types of signals

15. What is meant by modulation. What is meant by band width of information signal?

16. Name the types of modulations in analog communication.

17. What characteristic of modulated carrier wave does vary in amplitude modulation?

18. . What characteristic of modulated carrier wave does vary in frequency modulation

19. what is an analog communication system? 20. 2. what is meant by the term modulation? 21. what is the essential requirement transmitting a microwave from one point to another on the earth?

22. what type of modulation is required for commercial broadcast of voice signals? 23. what is geostationary satellite? 24. suggest two methods by which the range of transmission by a TV Tower can be increased?

25. 8. what is transponder?

26. How is an artificial satellite helpful in telecommunication?27. what is ground wave?

1. Write the functions of the following in communication systems: (i) Transducer (ii) Repeater 2. Distinguish between any two types of propagation of (i) frequency range over which they are applicable (ii) communication systems in which they are used. 3. (i) Write the factors that prevent a baseband signal of low frequency to be transmitted over long distances. (ii) What is to be done to overcome these factors? Draw a block diagram to o signal. 4. A transmitting antenna at the top of a tower has a height of 36 m and the height of the receiving antenna is 49 m. What is the maximum distance between them, for satisfactory communication in the LOS mode ? (Radius of earth = 6400 km).5. What does the term ‘LOS communication’ mean ? Name the types of waves that are used for this communication. Give typical examples, with the help of a suitable figure, of communication systems that use space wave mode propagation.6. Write two factors justifying the need of modulation for transmission of a signal.7. Explain the function of a repeater in a communi

8 Write the functions of the following in communication systems:

(i) Transmitter (ii) Modulator

In the block diagram of a simple modulator for

obtaining an AM signal, shown in the figure,

Identifythe boxes A and B. Write their functions.

9 In the given block diagram of receiver,

identify the boxes labelled as

X and Y and write their functions.

10 .Why ground wave transmission signal is is restricted to only 1500 KHz.

11 .A T.V tower has a height of 500 m at a given place.

12 Calculate its coverage range if the radius of the earth is 6400 Km.

13 Label the unlabeled box in the given figure. Write its function.

14 draw the block diagram showing the important components of a communication system

15 Distinguish between analog and Digital16 .Explain why high frequency signals.

17 . why should transmitters broadcasting frequencies?

18 What is space wave communication write the range of freqwave communication.

satellite helpful in telecommunication?

SECTION-B (TWO MARKS) Write the functions of the following in communication systems:

2. Distinguish between any two types of propagation of Electromagnetic waves with respect to(i) frequency range over which they are applicable (ii) communication systems in which they are used. (i) Write the factors that prevent a baseband signal of low frequency to be transmitted over long

(ii) What is to be done to overcome these factors? Draw a block diagram to o

A transmitting antenna at the top of a tower has a height of 36 m and the height of the receivingm. What is the maximum distance between them, for satisfactory communication

the LOS mode ? (Radius of earth = 6400 km). What does the term ‘LOS communication’ mean ? Name the types of waves that are used for this

typical examples, with the help of a suitable figure, of communicationsystems that use space wave mode propagation. Write two factors justifying the need of modulation for transmission of a signal.Explain the function of a repeater in a communication system.

Write the functions of the following in communication systems:

In the block diagram of a simple modulator for

obtaining an AM signal, shown in the figure,

Identifythe boxes A and B. Write their functions.

In the given block diagram of receiver,

.Why ground wave transmission signal is is restricted to only 1500 KHz.

A T.V tower has a height of 500 m at a given place.

Calculate its coverage range if the radius of the earth is 6400 Km.

Label the unlabeled box in the given figure. Write its function.

draw the block diagram showing the important components of a communication

istinguish between analog and Digital Communications. xplain why high frequency carriers waves are needed for effective transmission of

. why should transmitters broadcasting programmers uses different

What is space wave communication write the range of frequencies suitable for

Electromagnetic waves with respect to

(i) Write the factors that prevent a baseband signal of low frequency to be transmitted over long

(ii) What is to be done to overcome these factors? Draw a block diagram to obtain the desired

A transmitting antenna at the top of a tower has a height of 36 m and the height of the receiving m. What is the maximum distance between them, for satisfactory communication

What does the term ‘LOS communication’ mean ? Name the types of waves that are used for this typical examples, with the help of a suitable figure, of communication

Write two factors justifying the need of modulation for transmission of a signal.

draw the block diagram showing the important components of a communication

waves are needed for effective transmission of

uses different carriers

uencies suitable for space

19 What is the range of frequencies used in satellite communication what is common between these waves and light waves?

20 Name the device used for data transmission from one computer to another justify the name.

21 What is ground wave Communication on what factors does the maximum Range propagation in this mode depend?

22 Mention the frequency at which TV signals are transmitted derive an expression for the range upto which signals can be transmitted by an antenna incommunication.

SECTION1.Define the term modulation. Draw a block diagram of a simple modulator for obtaining AM signal. 2. Distinguish with the help of suitable diagrams between ground wave and sky wave modes of propagation. Mention the frequency range of the waves in these modes of propagation.3. Explain, with the help of a suitable diagram, the space wave mode of prop examples in communication system where this mode is used. What is the frequency range of these waves? Give reason for using this range of frequency.4. Draw a plot of the variation of amplitude versus modulation index. State its importance for effective amplitude modulation.5. What is space wave propagation? Give two examples of communication system which use space wave mode. 6 A TV tower is 81 tall. Calculate the maximum distance up The tower can be received. 7 With block diagram explain demodulation.8 A transmitting antenna at the top of a tower has a height of 36 m and the height of the receiving anten

m. What is the maximum distance between them, for satisfactory communication in the LOS mode ? (Radius of

earth = 6400 km).

9 What does the term ‘LOS communication’ mean? Name the types of waves that are used for this

communication. Give typical examples, with the help of a suitable figure, of communication systems that use

space wave mode propagation..

10 . Ground receiver station is receiving a signal at (i) 5 MHz and (ii )100 MHz transmitted from a ground

transmitter at a height of 300 m, loca

the signal is coming via space wave or sky wave propagation or satellite transponder. Radius of earth = 6.4 x

106 m. Nmax of the Ionosphere = 10

11 A schematic arrangement for transmitting a message signal (20 Hz to 20 KHz) is given below: Give

two drawbacks from which this arrangement suffers. Describe briefly with the help of a block diagram the

alternative arrangement for the transmission

What is the range of frequencies used in satellite communication what is common between these waves and light waves? Name the device used for data transmission from one computer to another justify

What is ground wave Communication on what factors does the maximum Range propagation in this mode depend? Mention the frequency at which TV signals are transmitted derive an expression for the range upto which signals can be transmitted by an antenna in

SECTION-C (THREE MARKS) Define the term modulation. Draw a block diagram of a simple modulator for obtaining AM

Distinguish with the help of suitable diagrams between ground wave and sky wave modes of propagation. Mention the frequency range of the waves in these modes of propagation.Explain, with the help of a suitable diagram, the space wave mode of propagation. Give two

in communication system where this mode is used. What is the frequency range of these waves? Give reason for using this range of frequency. Draw a plot of the variation of amplitude versus w for an amplitude modulated wave. Definemodulation index. State its importance for effective amplitude modulation. . What is space wave propagation? Give two examples of communication system which use space

tall. Calculate the maximum distance up to which the signal transmitted from

With block diagram explain demodulation. A transmitting antenna at the top of a tower has a height of 36 m and the height of the receiving anten


What does the term ‘LOS communication’ mean? Name the types of waves that are used for this

examples, with the help of a suitable figure, of communication systems that use

. Ground receiver station is receiving a signal at (i) 5 MHz and (ii )100 MHz transmitted from a ground

transmitter at a height of 300 m, located at a distance of 100 km from the receiver station. Identify whether


m. Nmax of the Ionosphere = 1012

/ m3..

t for transmitting a message signal (20 Hz to 20 KHz) is given below: Give


alternative arrangement for the transmission and reception of the message signal.

What is the range of frequencies used in satellite communication what is common

Name the device used for data transmission from one computer to another justify

What is ground wave Communication on what factors does the maximum Range

Mention the frequency at which TV signals are transmitted derive an expression for the range upto which signals can be transmitted by an antenna in LOS

Define the term modulation. Draw a block diagram of a simple modulator for obtaining AM

Distinguish with the help of suitable diagrams between ground wave and sky wave modes of propagation. Mention the frequency range of the waves in these modes of propagation.

agation. Give two in communication system where this mode is used. What is the frequency range of

ulated wave. Define

. What is space wave propagation? Give two examples of communication system which use space

to which the signal transmitted from

A transmitting antenna at the top of a tower has a height of 36 m and the height of the receiving antenna is 49


What does the term ‘LOS communication’ mean? Name the types of waves that are used for this

examples, with the help of a suitable figure, of communication systems that use

. Ground receiver station is receiving a signal at (i) 5 MHz and (ii )100 MHz transmitted from a ground

ted at a distance of 100 km from the receiver station. Identify whether


t for transmitting a message signal (20 Hz to 20 KHz) is given below: Give


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