Class XII Physics Assignment

8/11/2019 Class XII Physics Assignment

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PHYSICS ASSIGNMENT

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Electric Charges and Fields

Q.1 (i) Can two equipotential surfaces intersect each other?(ii) Two chargesq and +q are located at points A (0, 0, -1) and B (0, 0, +1) respectively. How

much work is done in moving a test charge from p (7, 0, 0) to Q (-3, 0, 0)? (2 marks)Q.2 Can two equipotential surfaces intersect each other?

Q.3 Deduce an expression for electric potential due to dipole at a point in general? (3 marks)

Q.4 What is the work done in moving a test charge q through a distance of 1cm along the equatorial axesof dipole? (1 mark)

Q.5 The graph shows the variation of voltages V across the plates of two capacitors A & B versusincreases of charge, Q stored on them. Which of the two capacitors has HIGHERCAPACITANCE? (2 marks)

Q.6 Use gausss law to deduce an expression for electric field due to uniformly charged plate/sheet?(3 marks)

Q.7 Force of attraction b/w two point charges placed at distance d apart in a medium is F. Whatshould be the distance apart in the same medium so that the force of attraction b/w them becomes

9F? (2 marks)

Q.8 Two rectangular metal plates, each of area A are kept parallel to each other at a distance d apart toform a parallel plate capacitor. If the area of each of the plates is doubled and their distance ofseparation decreases to 1/2 of its initial value. Calculate the ratio of their capacitance in the twocases? (2 marks)

Q.9 Show that the electric field is always perpendicular to an equipotential surface? (2 marks)

Q.10 Two parallel plate capacitors X and Y, have the same area of plates and same separation b/w them.

X has air between the plates while Y contains a dielectric of medium r= 4. Calculate (3 marks)(a) capacitance of each capacitor if equivalent capacitance of the combination is 4 F.?(b) Calculate the potential difference b/w plates of X and Y?

(c) what is the ratio of electrostatic energy Y stored in X and Y?

Q.11 Define the term potential energy of charge q at a distance r in an external electric field? (1 mark)

Q.12 Two fixed point charges +4e and +e units are separated by a distance a. Where should the thirdpoint charge be placed for it to be in equilibrium? (2 marks)


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Q.13 Define the electric flux. Write its S.I. units. A charge 8.85 C is enclosed in a spherical surface ofradius R. Estimate the number of field lines emerging out from the point charge. If radius of sphere

is reduced to half, how would the flux through the surface change? (3 marks)

Q.14 Define electric field intensity. Write its S.I. unit. Write the magnitude and direction of electric fieldintensity due to an electric dipole of length ''2a'' at the midpoint of the line joining the two

charges? (2 marks)

Q.15 Two point charges 3 x 10-8

C and -2 x 10-8

C are located 15 cm apart in air. Find at what point on the

line joining these charges the electric potential is zero? (2 marks)

Q.16 Show that the electric field is always perpendicular to an equipotential surface?

Q.17 (a) Derive an expression for energy stored per unit volume in parallel plate Capacitor.

(b) A 10 F Capacitor is charged by a 30 v d.c. Supply and then connected t across an uncharged 50F Capacitor. Calculate the final potential difference across the combination and loss of energy inthe process? (5 marks)

Q.18 Derive expressions for the electric field due to a uniformly charges spherical shell at a point (I)INSIDE and (II) OUTSIDE the shell? (2 marks)

Q.19 S1and S2are two hollow concentric spheres enclosing charges q and 2q respectively.

(i) What is the ratio of electric flux through S1and S2?

(ii) How will the electric flux through sphere S1change is a medium of dielectric constant 5 isintroduced in the sphere S1in place of air ? (2 marks)

Q.20 Sketch a graph to show how the charge Q acquired by a capacitor of capacitance C varies withincrease in potential difference between the plates? (1 mark)

Q.21 An electric dipole is placed in uniform electric field translatory motion (5 marks)

(i) Show that dipole does not has translator motion.(ii) Also find out an expression for torque on dipole.(iii) State conditions for stable and unstable equilibrium.

Q.22 Define the term electric dipole moment of a dipole. State its S. I. unit ? (1 mark)

Q.23 A parallel plate capacitor is charged to a potential difference V by a source. The capacitor is thendisconnected from the source. If the distance b/w the plates are doubled stale with reason how willfollowing change. (3 marks)(i) electric field between the plates.?

(ii) Capacitance and

(iii) energy stored in the capacitor.?Q.24 Two chargesq and +q are located at points A (0, 0, -a) and B (0, 0, +a) respectively. How much


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PHYSICS ASSIGNMENT

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work is done in moving a test charge from p (7, 0, 0) to Q (-3, 0, 0)?

Q.25 A charge q is enclosed by a spherical surface of radius R. If the radius is reduced to half, how wouldthe electric flux through the surface change? (1 mark)

Q.26 A 500 c charge is at the centre of square of side 10 cm. find the work done in moving a charge of

10 c b/w two diagonally opposite points on the square? (1 mark)Q.27 Define ideal dipole. Deduce an expression for electric field intensity due to electric dipole at a point

on perpendicular bisector.? (3 marks)

Q.28 An electric field is uniform and has direction in the +ve x direction for +ve x and uniform with the

same magnitude but in theve x direction forve x. N/C for x > 0 andN/C, [x< 0]. A right circular cylinder of length 20 cm and radius 5 cm has its centre at the origin andits axis along x axis so that one face is at x = +10cm and other face is at x = -10cm. Find the netcharge within the cylinder? (3 marks)

Q.29 A charge Q is placed on a large spherical conducting shell of radius R another small conductingsphere of radius r carrying charge q is introduced inside the large shell and is placed at its centre.

Show that Charge will How from inner sphere to shell . when connected together Name the devicewhich works on this fact mention its application? (5 marks)

Q.30 Which orientation of an electric dipole in a uniform electric field would correspond to a stableequilibrium? (1 mark)

Q.31 Derive an expression for the energy stored in a parallel plate capacitor. (3 marks)

Q.32 Three identical capacitors c1, c2and c3of capacitance 6 F each are connected to a battery of 12v.Find : (3 marks)(a) charge on each capacitor?(b) equivalent capacitance of network?(c) energy stored in the network?

Q.33 Draw the electric field lines due to charge system such that q1 + q2 = 0? (1 mark)

Electrostatic Potential and Capacitance

Q.1 What would be the work done if a point charge +q is taken from a point A to the point B on thecircumference of a circle with another point charge +q? (1 mark)

Q.2 What will be effect of dielectric slab on capacitance when space b/w the plates of capacitor is filled

with diaelectric slab? (1 mark)

Q.3 Deduce an expression for potential due to electric dipole at a point lying on its Bisector. (2 marks)

Q.4 Three point charges of +2c; and -3c are Kept at the vertices A, B and C respectively of anequilateral triangle of side 20cm. what should be the sign and magnitude of the charge to be placedat the mid-point M of side BC. So that charge at a remains in equilibrium. (3 marks)

Q.5 Deduce an expression for energy density of a parallel plate capacitor. (3 marks)


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Q.6 A10F capacitor is charged by a 30V d.c and then connected across the uncharged 50F capacitor.Calculate (i) the final potential difference across the combination and initial & final energies. (3

marks)

Q.7 The electric field and potential at any point due to a point charge kept in air is 20NC- and 10JC-

respectively . Calculate the magnitude of charge. (2 marks)

Q.8 Show that electric field is always perpendicular to an equipotential surface. (2 marks)

Q.9 (i) Explain the principle of working of a parallel plate capacitor.

(ii) Deduce an expression for equivalent capacitance when two capacitors are connected inparallel. (5 marks)

Q.10 Show that energy stored in a parallel plate capacitor is 1/2CV2. (2 marks)

Q.11 The graph shows the variation of potential difference V across the plates of two capacitor A and Bverses charge Q stored . Which of the two has higher capacitance? (2 marks)

Q.12 Two chargesq and +q are located at A(0,0,-a) and B(0,0,+a) respectively . How much work is done

in moving a test charge from P(7,0,0) to Q (-3,0,0)? (2 marks)

Q.13 Derive an expression for capacitance of a parallel plate capacitor. (2 marks)

Q.14 What is the physical importance of the line integral of an electric field? (1 mark)

Q.15 Can two equipotential surfaces intersect each other. (1 mark)

Q.16 With the help of labeled diagram, describe the construction and working of Van de graphgenerator. (5 marks)

Q.17 An electric dipole of length 2cm is placed with its axis making an angle of 60owith respect to a

uniform electric field of 105N/C. If it exists a torque of 8 , Calculate (3 marks)

(i) Magnitude of charge

(ii) Potential energy of the dipoleQ.18 How much energy will be started in a capacitor? (1 mark)

Q.19 Draw the equipotential surfaces due to charge q > 0. (1 mark)

Q.20 A point charge q is placed at 0 is VPVQpositive or negative when (i) q > 0 (ii) q < 0. (1 mark)

Q.21 Deduce an expression for capacitance of a parallel plate capacitor when space between the plates isfilled with dielectric slab. (3 marks)

Q.22 State gauss theorem. Use gauss theorem to obtain the expression for electric field due to linearly

charged wire. Sketch the graphical variation of electric field with distance r from wire. (5 marks)


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Current Electricity

Q.1 You are asked to measure of emf of a cell. Which instruments will you use a high resistancevoltmeter or a potentiometer? (1 mark)

Q.2 A cylindrical wire is streched to increase its length by 5%. Calculate the percentage change in itsresistance? (2 marks)

Q.3 Show the Graphical variation of resistivity with temprature for conductor & semiconductor? (2marks)

Q.4 A cell of emf E and internal resistance r are connected across a variable resister R. Plot a Graph.Sshowing the variation of terminal potential V with resistance r? (2 marks)

Q.5 Describe a method to find out the resistivity of a material in laboratory along with necessary circuitdiagram? (5 marks)

Q.6 What is meant by sensitivity of a potentiometer? A battery E1of 4V and variable resistance R areconnected in series with wire AB. Length of wire is 1m. When a cell of emf E 2= 1.5V is connectedb/w A & C , no current flows through E2. Length of AC is 60 cm. (5 marks)

(I) Find the potentiometer difference b/w A & B

(II) Would the method work if the battery E1is replaced by a cell of emf of 1v.

Q.7 Find the value of unknown resistance X in the following circuit, if no current flows through thesection AO. Also calculate the current drawn by the circuit from the battery of emf CV? (3 marks)

Q.8 What is the effect of heating of a conductor on drift velocity of free electrons? (1 mark)

Q.9 (a) VI graph for a metallic wire at two different tempratures T1& T2is shown. Which of the twotemprature T1& T2is Higher and why?

(b)Using current conduction in conductor verify ohms law. (5 marks)

Q.10 Three indentical cells each of emf 4v and internal resistance r are connected in series to a 6

resistor. If the current flowing in the circuit is 1.5A. What will be internal resistance of each cell?(2 marks)

Q.11 A wire of resistivity is streched to twice its length. What will be its new resistivity? (1 mark)

Q.12 The length of a potentiometer wre is 600 cm and it carries a current of 40mA. For a cellof emf 2Vand internal resistance 10 , the null point is found to be at 500 cm. If a voltmeter is connectedacross the cell, balance length is decreased by 10cm. Find:- (3 marks)

(i) The resistance of whole wire(ii) Reading of voltmeter(iii) Resistance of voltmeter

Q.13 Two primary cells of emf E1& E2(E1>E2) are connected to the potentiometer wire AB. If thebalancing length for the two combination of the cells are 250cm and 400 cm? Find the ratio of E1 &


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E2. (2 marks)

Q.14 Define the term resistivity. Derive the expression for the resistivity of a conductor in terms ofnumber density? (2 marks)

Q.15 How does the drift velocity of electrons in a metallic conductor change; if the length of conductor is

doubled by stretching it, keeping the applied potential difference constant? (1 mark)Q.16 The P.d. across a given copper wire is doubled .What happens to the drift velocity of charge

carriers? (1 mark)

Q.17 Show that where is conductivity and is electric field? (2 marks)

Q.18 Potential difference across terminals of a cell were measured(in volts) against different currents(in

amperes) flowing through the cell. A graph was drawn which was a straight line. Using the datagiven detemine : (3 marks)(I) emf of each cell(II) Internal resistance of each cell

Q.19 Two wires of equal length, one of copper and the other of magnin have the same resistance. Whichwire is thicker? (1 mark)

Q.20 Draw a circuit diagram to find unknown resistance using meter bridge and write necessarymathematical relation used for it. (2 marks)

Q.21 Explain how does the resistivity of a conductor depend upon number density of free electrons &relaxation time? (2 marks)

Q.22 A Potentio meter wire of length 1m is connected to a driver cell of emf 3v as shown in figure :

When a cell of 1.5 volt emf is used in secondary circuit the balance point is found to be 60 cm . Onreplacing this cell and using a cell of unknown emf, the balance point shifts to 80 cm Calculate theunknown emf (3 marks)

(1) Calculate the unknown emf.(2) If the driver cell is replaced with a cell of emf 1V. What will be effect on nullpoint.(3) Does the high resistance R effect the null point.

Q.23 State the principle of potentiometer. Draw a circuit diagram used to compare the emf of two primarycells. Write the formula used? (3 marks)

Q.24 For the potentiometer circuit shown in the figure, points X and Y represent the two terminals of an


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unknown emf E. A student observed that when the jockey is moved from the end A to the end B,deflection in galvanometer remains in same direction. What may be two possible faults? (2

marks)

Q.25 Two cells E1and E2have an emf 5V and 9v and internal resistance of 0.3? & 1.2? respectively.Calculate the current flowing through 3?? (2 marks)

Q.26 The sequence of bands marked on a carbon resistor are brown black, brown gold.Write the value ofresistance? (1 mark)

Q.27 Using Kirchhoffs law calculate the value of current I1, I2and I3. (3 marks)

Q.28 A conductor of length l connected to a d.c. source of potential V. If the length of the conductor is

tripled by streching it keeping V constant. Explain how do the following factors vary in theconductor? (2 marks)

(1) Drift speed of electrons(2) Resistence(3) Resistivity

Q.29 A heating element using nichrome connected to 230 v supply draws an initial 3.2 A, which settlesafter a few seconds at a steady value of 2.8 A. What is the steady temprature of heatingelement.Even Romm temp. 27

OC, =1.7 x 10-4

OC

-1. (3 marks)

Q.30 Write the S.I. Unit of resistivity? (1 mark)


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MAGNETISM

Q.1 Write the relation for the force acting on a charge carrier q moving with a velocity through a

magnetic field in vector rotation. Using this relation deduce the conditions under which force willbe maximum & minimum. (3 marks)

Q.2 An element is placed at the origin and carries a large current I = 10A . What is themagnetic field on the Y-axis at a distance 0.5m. given ?x = 1cm? (2 marks)

Q.3 Write down Biot- savart law? (1 mark)

Q.4 A galvanometer has a resistance of 30. It gives full scale deflection with a current of 2mA.Calculate the value of the resistance needed to convert it into an am meter of range 0.3A ? (2marks)

Q.5 How will the magnetic field intensity at the centre of circular coil of radius R is changed if currentthrough coil doubled and radius of coil is halved? (1 mark)

Q.6 An electron beam projected along +x axis, experiences a force due to a magnetic field along the +y

axis. What is the direction of magnetic field? (1 mark)

Q.7 State the principle of working of a cyclotron. Write two uses of this machine. (2 marks)

Q.8 What is the resistance of an ideal volt meter? (1 mark)

Q.9 A particle of mass m with charge q moving with a uniform speed ? normal to a uniform magneticfield B, describes a circular path of radius r. Describe an expression for the (i) time period of

revolution & (ii) Kinetic energy of the particle. (3 marks)

Q.10 A charged particle of mass m charge q moving at uniform velocity ? , enters a u niform magneticfield B acting normal to plane of paper. Show that charge to mass ratio will be guneas ? /rB. (2

marks)

Q.11 Two wires of equal lengths are bent in the form of two loops one of the loop is square shaped whereas, the other loop is circular. These are suspended in a uniform magnetic field and the same currentis passed through them. Which loop will experience greater torque? (1 mark)

Q.12 Define the S.I. unit of magnetic field? (1 mark)

Q.13 A charge moving at right angles to uniform magnetic field does not under go change in kineticenergy why? (1 mark)

Q.14 A proton and an alpha particle having the same K.E. are in turn allowed to pass through a uniformmagnetic field perpendicular to their direction of motion Compare the radii of paths of proton & particle. (3 marks)

Q.15 Two parallel coaxial circular coils of equal radius R and equal number of turns N. carry equal

current I in the same direction and are separated by a distance 2R. find the magnitude and directionof the net magnetic field at mid point of line joining their centers? (3 marks)

Q.16 Which one of the two , an Ammeter or a millimetre , has a higher resistance and why? (2 marks)

Q.17 A circular coil of 100 turns, radius 10cm carries a current of 5A. It is suspended vertically in auniform horizontal magnetic field of 0.5T, the field lines making an angle of 60o with the plane ofthe coil. Calculate the magnitude of torque that must be applied on it to prevent it form turning.(3 marks)

Q.18 Draw the magnetic field lines due to a circular current carrying loop? (1 mark)

Q.19 Using Amperes circuital law, obtain an expression for the magnetic field along the axis of a currentcarrying solenoid of length L and having N number of turns? (3 marks)

Q.20 Define the current sensitivity and voltage sensitivity of a galvanometer. (2 marks)


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MOVING CHARGES

Q.1 Derive the magnetic dipole moment due to an electron orbiting in circular path of radius r withvelocity?? (2 marks)

Q.2 Deduce an expression for magnetic field intensity due to a magnetic dipole at a point lying on itsnormal bisector? (3 marks)

Q.3 Why should the material used making permanent magnet have high coercivity?

Q.4 Derive an expression for torque experienced by a magnetic dipole in a uniform magnetic field? (3

marks)

Q.5 Define the terms retentively & coercivity

Q.6 Mention two characteristic properties to distinguish b/w diamagnetic and paramagnetic materials

? (2 marks)

Q.7 Explain the phenomenon of hysteresis in magnetic materials? (3 marks)

Q.8 Distinguish between paramagnetic, diamagnetic and ferromagnetic material. (3 marks)

Q.9 Steel is preferred for making permanent magnets why? (1 mark)

Q.10 A current loop is considered as a magnetic dipole. Explain. (2 marks)

Q.11 (i) What kind of material is used to make core of an electric transformer? Justify the answer .

(ii) A bar magnet of moment 1.5 JT-1is aligned with the direction of a uniform magnet field of0.22T. Calculate the amount of work done to turn the magnet so as to align its magnetic moment

(a) Normal to field direction (b) opposite to field direction

Q.12 What should be the orientation of magnetic dipole in uniform magnetic field so that potential energyis minimum? (1 mark)

Q.13 A uniform magnetic field gets modified as shown, when two specimens X and Y are placed inuniform field. Identify X and Y. (2 mark)

Q.1 Explain, with the help of diagram , the principle and working of an a.c. generator . Write theexpression for induced emf. (3 marks)

Q.2 A 0.5m long metal rod PQ completes the circuits as shown . The area of the circuit is perpendicularto the magnetic field of flux density 0.15T. If the resistance of the total circuit is 3 . Calculate theforce needed to move the rod in the direction as indicated with constant speed of 2ms

-1.?


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Q.3 A cylindrical bar magnet is kept along the axis of a circular coil and near it as shown in the diagram.Will there be any induced emf at terminals of the coil, when the magnet is rotated (a) about its ownaxis (b) about an axis perpendicular to the length of magnet. (2 marks)

Q.4 Circular coil of radius 8cm and 20 turns rotates about its vertical diameter with an angular speed of

50s-1

. In a uniform horizontal magnetic field of magnitude 30 x 10-2

T. Find the maximum andaverage value of emf induced in the coil? (2 marks)

Q.5 The circuit arrangement given below shows that when a.c. passes through coil A, the current startsflowing in the coil B (2 marks)

(i) State the underlying principle involved.

(ii) Mention two factors on which the current produced in coil B depends.

Q.6 State Lenzs law. Give one example to illustrate the law. The lenz law is a consequence of theprinciple of conversation of energy. Justify the statement. (3 marks)

Q.7 Define 1mH Inductance. (1 mark)

Q.8 What is induced current? (1 mark)

Q.9 A coil is connected to a voltmeter V and the other coil to an alternating current source. If a largecopper sheet is placed between the the two coils, how does the included emf in the coil change due

to current in the coil B? (1 mark)


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Q.10 Write S.I. Unit of magnet flux. Is it a scalar or a vector quantity. (1 mark)

Q.11 A circular coil of N turn and radius R is kept normal to a magnetic field given by B=Bo cos wt. Statethe rule which helps to detect the direction of induced current? (1 mark)

Q.12 Explain briefly, with the help of a labeled diagram the basic principle of working of a.c. generator.

In an a.c. generator coil of N turns and area A is rotated at rotation per second in a uniformmagnetic field B. Write the expression of the emf produced. (5 marks)

Q.13 State the law that gives the polarity of induced emf.

Q.14 The fig shows two identical rectangular loops 1 and 2 placed on a table along with a straight linecurrent carrying conductor b/w them.

(i) What will be the directions of the induced currents in the loops when they are pulled away fromthe conductor with same velocity?

(ii) Will the emf induced in the two loops be equal? (2 marks)

Q.15 Show that energy stored in an inductor L, when a current I is established through it is 1/2LI . (2marks)

Q.16 Define mutual inductance . Deduce an expression for coefficient of mutual inductance for pair oftwo concentric circular coil. (3 marks)

Q.17 An a.c. generator consist of a coilof 100 turns and crossectional area of 3m , rotating at a constantangular speed at 60 rad/s in a uniform magnetic field of 0.04T the resistance of coil is 500? .Calculate the maximum current drawn from the generator and maximum power dissipation in thecoil. (5 marks)

Q.18 If the number of turns of a solenoid is doubled, keeping the other factors constant, how does the self

inductance of the coil changes? (1 mark)

Q.19 What are the eddy currents ? Write their two applications. (2 marks)


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Q.20 Write S.I. unit of mutual inductance. Give two factors on which the coefficient of mutual inductancebetween a pair of coil depends. (2 marks)

Q.21 State faradays law of electromagnetic induction. (3 marks)

Q.22 Derive an expression for induced emf and induced current, when a conductor of length L is moved

with a uniform velocity V normal to uniform magnetic field B. Assume the resistance of theconductor be R. (3 marks)

Q.23 How is the Mutual inductance of a pair of coils affected when (3 marks)

(i) Separation b/w the coils is increased.

(ii) the number of turns of each coil is increased.

(iii) A thin iron sheet is placed between the two coils ; other factors remaining the same ?

Q.24 A metallic rod of length L is rotated at a constant angular speed w , normal to a uniform magneticfield B. Derive an expression for the current included in the rod. If the resistance of the rod is R.

(3 marks)

Q.25 A rectangular coil of N turns, area A is held in a uniform magnetic field B. If the coil is rotated at asteady angular speed w, deduce an expression for the induced emf in coil at any time. (2 marks)

Q.26 Following figure shows a bar magnet M falling under gravity through an air coil C. Plot a graphshowing variation of induced emf (e) with time t. (3 marks)

Q.27 Name the physical quantity whose S.I unit is Wbm-

? (1 mark)

Q.28 Define coefficient of mutual inductance of two coils. A secondary coil of n2turns is wound on along solenoid of area of cross section A having a primary coil of n1turns per unit length. What is themutual inductance of the two coils ? (3 marks)

Q.29 Define self inductance . Derive an expression for self induction of a long solenoid of length L, crosssection area A, having N number of turns. (3 marks)

Q.30 Derive an expression for the self inductance of a long solenoid. State the laws to determine thedirection of induced current. (5 marks)


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ALTERNATING CURRENT

Q.1 An a.c source of 100 V rms, 50Hz is connected across a 20 resistor and a 2mH inductor in series.

Calculate the Impedance of the circuit and rms current. (2 marks)

Q.2 For a given a.c. circuit distinguish between resistance reactance and impedance.(2 marks)

Q.3 Show that an ideal capacitor does not dissipate power. (2 marks)

Q.4 An Inductor 200mH , capacitor 5F, resistor 10? are connected in senses with 100 V , variablefrequency a.c. source. Calculate the

(i) Frequency at which power factor of circuits is unity.(ii) Current amplitude at this frequency(iii) Q factor (3 marks)

Q.5 State the condition under which the phenomenon of resonance occurs in L.C.R circuit. Plot a graphshowing the variation of current with frequency. (2 marks)

Q.6 Show mathematically that in A.C. circuit containing only inductance , the current lags behind thevoltage by a phase of /2. (3 marks)

Q.7 A variable frequency 230V alternating voltage source is connected across a series combination ofL= 5H C = 80F& R = 40 calculate

(i) Angular frequency of source which drives the circuit in resonance(ii) Impedance of circuit at resonance(iii) Amplitude of current at resonance (3 marks)

Q.8 What is the power dissipated in a.c. circuit in which voltage and current are given by V =230sin(t+/2) and I = 10sinwt? (1 mark)

Q.9 Derive an expression for the impedance of an a.c. circuit with series L.C.R Combination. (3marks)

Q.10 Draw the graph showing the variation of inductive reactance and capacitive reactance withfrequency of applied a.c. voltage source. (2 marks)

Q.11 Given circuit diagram shows a series L.C.R circuit connected to variable frequency 230V source(5 marks)

(i) Determine the source frequency which drives the circuit in resonance(ii) Obtain the Impedance of circuit & amplitude of at the resonating frequency(iii) Determine the rms potential drop across the three elements of circuits

Q.12 What are eddy currents ? How are these produced? In what sense are eddy currents consideredundesirable in a transformer? (3 marks)

Q.13 Explain with the help of a labeled diagram the underlying the principle and working of a step downtransformer. (3 marks)

Q.14 An alternating voltage of frequency f is applied across LCR circuit. Let frbe the resonance

frequency of the circuit . Will the current in the circuit lag, lead or remain phase with the appliedvoltage when (i) f > fr (ii) f < fr ? (2 marks)


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Q.15 State the principle of working of transformer. (1 mark)

Q.16 Given below are two electric circuits A and B

Calculate the ratio of power factor of circuit B to power factor of circuit A. (3 marks)

Q.17 A capacitor of capacitive reactance 100? is put across an alternating voltage v=200sin100t. Write anexpression for the current in the circuit. (1 mark)

Q.18 A pure inductor is connected across the a.c. source. Show mathematically that the current in it lagsbehind the applied voltage by /2. What is inductive reactance? (3 marks)

Q.19 What will be average value of a.c. signal I = 10sin314t for time interval t = 0 to t = /w? (1 mark)

Q.20 Show that the ideal inductor does not dissipate power over a complete a.c cycle. (2 marks)

Q.21 An a.c. source of 100v 5Hz source is connected across 10 resistance. Write the expression for

instantaneous current and power dissipation across resistance. (2 marks)

Q.22 Write the relation between peak value and r.m.s value of current? (1 mark)

Q.23 A solenoid with iron core and a bulb are connected to a d.c. source. How does the brightness of the

bulb change, when an Iron core is removed? (1 mark)

Q.24 1F capacitor is connected to 220 V 50Hz source. Find the peak value of voltage across thecapacitor? (2 marks)

Q.25 A bulb of resistor 10? connected to an Inductor of inductance L is in series with an a.c. source

marked 100v 50Hz. If phase angle between the voltage and current is /4 radian. Calculate the valueof L. (2 marks)

Q.26 Calculate current drawn by the primary of a transformer which steps down 200V to 20V to operate adevice of resistance 20 . Assume the efficiency of transformer tobe 80%. (2 marks)

Q.27 Mention two causes for the power loss in a transformer. (1 mark)

Q.28 The power factor of an a.c. circuit is 0.5, what will be the phase difference b/w voltage andcurrent? (1 mark)

ELECTROMAGNETIC WAVE

Q.1 Sketch a schematic diagram depicting electric and magnetic fields for an electromagnetic wavepropagating along z-direction. (2 marks)

Q.2 The oscillating magnetic field in a plane electromagnetic wave is given by BY=8 x 10-

sin(20 x 10 t

+ 300x)T.Calculate the wavelength of e.m. wave. Write down the expression for oscillatingelectric field. (2 marks)


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Q.3 Write the expression for the velocity of e.m. waves in terms of perimitivity and permeability. (1mark)

Q.4 Name the constituent radiation of e.m. spectrum which

(i) is used in satellite communication

(ii) is used for studying crystal structure(iii) is similar to radiation emitted during decay of nuclei(iv) has wavelength b/w 390nm and 770nm(v) is absorbed from sunlight by ozone layer(vi) produces intense heating effect

Q.5 Arrange the following electromagnetic radiation in ascending order of their frequencies.

(a) Microwaves(b) Radio waves(c) X-rays(d) Gamma rays

Write two uses anyone of this. (2 marks)

Q.6 Identify the electromagnetic radiations as given : frequency = 1020

HZ. (1 mark)

Q.7 Identify the following electromagnetic radiations as given below Write one application of each ?(3 marks)

(a) 1nm(b) 10-12m

(c) 10-8

m

Q.8 Find the wave length of e.m. waves of frequency 5 x 1019 Hz. Give its two applications. (2

marks)

Q.9 Give two uses each of (i) radio waves (ii) Microwaves. (3 marks)

Q.10 Write the order of frequency range and one use each of the following e.m. radiation (i) Micro waves(ii) U.V rays (iii) Gamma rays ? (3 marks)

Q.11 From the following, identify the e.m. waves having (i) maximum (ii) Minimum frequency. (2marks)

(a) Radio waves(b) Gamma rays(c) Visible light

(d) Microwaves(e) U.V. rays

(f) I.R.rays

Q.12 Give a reason to show that microwaves are better carrier of signal for long range transmission. (1mark)

Q.13 The electric field of plane an wave is given Ex=0 , Ey=0, Ez=0.5cos{2 x 108(t-4c)}

(i) What is dirnof propagation of wave?

(ii) Compute the components of magnetic fields. (3 marks)

Q.14 Name the EM waves used for treatment of cancer tumors. (1 mark)Q.15 Write the following radiations in ascending order in respect of their frequencies X-ray microwaves


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radio waves. (1 mark)

Q.16 Identify the following e.m. radiation as per wave length given below. Write one application ofeach. (3 marks)(i) 10-3nm(ii) 10

-3m

(iii) 1nm

Q.17 Name the following constituent radiation of electromagnetic radiation which is suitable for

(a) Radar system used in aircraft navigation(b) Treatment of cancer tumors

Write two application of each of them. (3 marks)

Q.18 Draw a sketch of a plane e.m. wave propagating along x axis. Depict clearly the directions of

electric and magnetic field varying sinusoidally. (2 marks)

Q.19 Electromagnetic radiations with wavelength

(i) 1are used to kill germs in water purifiers(ii) 2 are used in T.V communication system(iii) 2plays an important role in maintaining the earths warmth.

Name the part of e.m. spectrum to which these radiation belong. Arrange these radiation indecreasing order of wavelength. (2 marks)

Q.20 The oscillating electric field of an electromagnetic wave is given by EY=30 sin(2 x 1011t + 300x)

Vm-1

. Find the dirnof propagation of wave and write down the expression for magnetic field ? (2

marks)

Q.21 Which part of the electromagnetic spectrum has the largest penetrating power?(1 mark)

Q.22 Mention four properties of em waves. (2 marks)

Q.23 What is the ratio of speed of infrared rays and ultra violet rays in vacuum? (1 mark)

Q.24 Name the electromagnetic radiation used for viewing objects through haze and fog. (1 mark)

Q.25 The magnitude of magnetic field in a plane e.m. wave is given as BX= 0, BY= 2 x 10-7

sin(0.5 x 103

x + 1.5 x 1011

t)T. (3 marks)

(a) Determine the wavelength and frequency of wave.(b) Write an expression for the electric field.

Q.26 Name the electromagnetic radiation to which waves of wavelength in the range 10-2 m belong. Giveone use of this part of Em spectrum. (1 mark)

Q.27 Why are infrared radiations referred to as heat waves also? Name the radiations which are next to

these radiations in spectrum having (i) shorter wavelength and (ii) longer wavelength. (2 marks)

Q.28 Name the EM waves used for studying crystal structure of solids. (1 mark)

Q.29 A plane electromagnetic wave of frequency 25MHz travels in free space along the x-direction at a

particular point in space and time . Determine the at this time. (3 marks)


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RAY OPTICS & WAVE OPTICS

Q.1 What is the value of refractive index of a medium of polarizing angle 60? (1 mark)

Q.2 How does the magnifying power of an astronomical telescope change when Diameter of objectiveis increased .Write the expression it. (2 marks)

Q.3 In single slit diffraction pattern how does the width of central maximum will be affected when (3marks)

(i) Light of smaller wave length is used(ii) Width of slit is reduced.(iii) Separation b/w slit and screen is reduced

Q.4 State the condition for diffraction to occurs. In the diffraction in single slit experiment, how wouldthe width and intensity of central maximum change if (3 marks)(i) Slit width is halved

(ii) Light of lower wave length is used .

Q.5 A beam of light converges to a point P. A lens is placed in path of the convergent beam 12 cm from

P. At what points does the beam converges of lens is.

(a) Convex lens of focal length 20 cm.(b) a concave lens of focal length 16 cm. (3 marks)

Q.6 In youngs experiment , the width of the fringes obtained with light of wave front6000 A is 2mm.

Calculate the fringe width if the entire apparatus is immersed in a liquid of medium of refractiveindex 1.33. (2 marks)

Q.7 Give the ratio of velocities of light rays of wave length 4000 A & 8000 A in vaccum. (1 mark)

Q.8 How can one distinguish an unpolarized light beam and a linearly polarized light beam. (2 marks)

Q.9 State the condition under which total internal reflection occurs. One face prism with a refractingangle of 30ocoated with silver. A ray incident on another face at angle of 45

ois refracted and

reflected from silver coated face and retrace its path. Find the refractive index of the material ofprism. (3 marks)

Q.10 (a) State the condition of total internal reflection of light to take place.Hence derive the expressionfor critical angle in terms of speed light in two medium.

(b) Draw the ray diagram to show the image formation for compound microscope in normaladjustment. (5 marks)

Q.11 Three light rays red ( R ) , Green (G) and Blue (B) are incident on a right angled prism a b c atface ab .the refractive index of the material of the material of prism for Red , Green and Blue

wavelength are 1.39, 1.44, respectively.

Out of three which ray will emerge out of face a c. (3 marks)

Q.12 The image of a candle is formed by a convex lens on a screen. The lower half of the lens is paintedblack to make it completely opaque .Draw the ray diagram to show the image formation. How willthis image be different from one obtained when lens is not painted. (2 marks)

Q.13 Describe an activity to distinguish polarized light and unpolarised light. (3 marks)

Q.14 A converging lens of refractive index 1.5 is kept in a liquid having same refractive index .Whatwould be power of lens in this medium. (1 mark)

Q.15 For reflection of plane wave front at plane reflecting surface; construct the corresponding reflected

wave front. Using this diagram prove that angle of incidence is equal to angle of reflection. (2marks)


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Q.16 A ray of light passing through an equilateral triangular glass prism from air undergoes minimum

deviation when angle of incident is of angle of prism. Calculate the speed of light in prism. (2marks)

Q.17 Write the essential condition for total internal reflection. (1 mark)

Q.18 State two condition for sustained interference of light. (1 mark)

Q.19 A convex lens made up of glass of refractive index 1.5 is dipped in turn in :

(i) Medium A of refractive index 1.65(ii) Medium B of refractive index 1.33

Explain giving reasons ; whether it will behave as a converging or diverging lens. (3 marks)

Q.20 How does the power of a convex lens vary if the incident red light is replace d by violet light. (1mark)

Q.21 How does the angle of minimum deviation of a glass prism of refractive index 1.5 change , if it is

immersed in a liquid of refractive index 1.3. (1 mark)

Q.22 Give reason for following observations made from earth. (2 marks)

(i) Sun is visible before actual sunrise.(ii) Sun looks reddish at sunset

Q.23 A plane wave front is incident normally on a convex lens. Sketch the refracted wave front. (1

mark)

Q.24 What are coherent sources of light? Why are coherent sources are requested to obtained interferencepattern.

State three characteristics which distinguish the interference pattern to diffraction pattern. (5marks)

Q.25 Describe the diffraction of a light due to single slit. Plot a graph to show the variation of intensity ofpattern. (3 marks)

Q.26 How does the frequency of a beam of ultraviolet light change when it goes from air into glass?

(1 mark)

Q.27 Why does the bluish color predominate in a clear sky? (1 mark)

Q.28 Monochromatic light is incident an airglass interface. Compute the ratio of wavelength ofincident and refracted light. (2 marks)

Q.29 Draw a graph to show the variation of angle of Deviation D with that of the angle of incidencei

for a monochromatic ray of light passing through a glass prism of refracting angle A. Hence deducerelation. (3 marks)

Q.30 Find the ratio of intensities of points P and Q on a screen in a Youngs double slit experiment When

waves from S1and S2have Phase difference of (2 marks)

(i) O and (ii)

Q.31 Define the term Resolving power of a telescope. How does it get affected on (2 marks)


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(i) Increasing aperture of objective lens.(ii) Increasing focal length of objective.

Q.32 What do you mean by diffraction of light show the graphical variation b/w Intensity of diffraction

pattern with angle of diffraction. How Would be the width the of central maximum be affected when

width of slit is reduced. (5 marks)

Q.33 Define the term linearly polarized light. When does the intensity of transmitted light become

maximum, when a polaroid sheet is rotated b/w two crossed polaroids. (2 marks)

Q.34 Using the data given below , state as to which of the given lenses will you prefer to use as an eye

piece & an objective to design compound microscope. (2 marks)

Lens Power Aperture

A 20 D 0.02 m

B 10 D 0.02 m

C 10 D 0.05 m

D 1.0 D 0.1 m

Q.35 Draw a labeled ray diagram to show the image formation in reflecting type telescope. Write its two

advantages over a refracting type telescope. (3 marks)

Q.36 A double convex lens made of glass if refractive index 1.5 has its both surface of equal radii ofcurvature of 20 cm each. An a object of 5 cm height is placed at a distance of 10 cm from the lens.Find the position nature & size of image. (3 marks)

Q.37 What will be phase difference between any two point on a wave front? (1 mark)

Q.38 Draw a labeled ray diagram to show image formation in compound microscope. Write theexpression for its magnifying power. (2 marks)

Q.39 Using Huygens wave theory. Derive snells law. (2 marks)

Q.40 State Brewesters law. Show that Refracted and Reflected wave from a transparent medium isperpendicular to each other. (3 marks)

Q.41 Find the ratio of Intensity at two points X & Y on a screen in Youngs experiment when waves fromsources S1 and S2 have phase difference /3 and /2 respectively. (2 marks)

Q.42 In a single slit diffraction experiment , a slit of width d is illuminated by red light of wavelength650 nm .For what value of d will (3 marks)

(i) First minimum fall at angle of diffraction of 30 and(ii) The first maximum fall at an angle of diffraction of 30

Q.43 What will be effect on magnifying power of telescope when aperture of objective lens is decreased.

(1 mark)

Q.44 Derive an expression for the width of central maximum in diffraction through a single slit. (3marks)

Q.45 What do you mean by Interference of light. State two essential condition for sustained interference

.Write an expression for Fringes width. (3 marks)

Q.46 A convex lens made of material of refractive index n2is held in reference medium of index n1. Tracethe path of a parallel beam of height passing through the lens

When (i) n1 = n2 (ii) n1< n2 (iii) n1 > n2

Q.47 State and verify Brewesters law. (2 marks)

Q.48 A converging lens has a focal length of 20 cm in air .It is made of material if refractive index 1.6 .If


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it is immersed in a liquid of refractive index 1.3, What will be its new focal length. (3 marks)

Q.49 Draw a ray diagram to show the image formation by concave mirror when object is placed b/w focusslope using diagram. Derive the expression for magnification.(3 marks)

Q.50 What kind of wave front is will emerge from a point source? (1 mark)Q.51 What is interference of light? Write two essential condition for sustained interference fringes.

Draw a graph to show the variation of intensity versus position on screen in YDSE. When (a) boththe slits are open ( b) When one slit is closed .What is effect on interference pattern when screen ismoved closed to slit. (5 marks)

Q.52 How a wave front is related with light rays? (1 mark)

Q.53 Two source of intensity I1and I2undergo interference in Youngs experiment. Show

that , where a1and a2are the amplitude of two waves. (3 marks)

Q.54 Name the principal on which the working of optical is fiber is based. (1 mark)

Q.55 Define critical angle with reference to total internal reflection .Calculate the critical angle for air-glass interface when light deviates by 15o in glass medium when angle of incident is 45o. (2marks)

Q.56 Light of wavelength 600nm is incident on a single slit of width 0.5 mm at normal incidence.Calculate the separation b/w two dark bands on either side of central maximum , if the diffractionpattern is observed on a screen at 2m from slit. (2 marks)

Q.57 How does the intensity of central maxima change if the width of the slit is halved in a single slitdiffraction? (1 mark)

Q.58 In youngs experiment two coherent source are 1.5 mm apart and fringes are obtained at a distanceof 2.5 m from them. If the wavelength of light is 600 nm. Find the number of fringes in the pattern

which is 5.10-3 m wide. (2 marks)

Dual Nature of Matter and Radiation

Q.1 A particle of mass M at decays into two particle of masses m1and m

2having velocity v

1and v

2

respectively .Find the ratio of de Broglie wavelength of two particles. (2 marks)

Q.2 The energy level of an element are given below. Which corresponds to emission of spectral line of

wavelength 482nm? (3 marks)


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Q.3 The following graph shows the variation of stopping potential Vo with the frequency ? of theincident radiation for two Photosensitive metals X and Y.

(i) Explain which metal has smaller threshold wavelength .

(ii) Explain giving reason, which metal emits photoelectrons having smaller kinetic energy. (3marks)

Q.4 Radition of frequency 1015

Hz are in incident on two photosensitive surfaces A and B. Followingobservations are recorded:

Surface A: No photoemission takes place.Surface B: photoemission takes place but photoelectrons hace zero energy.

Explain the above observations on the basis of Einsteins photo electric equation. (3 marks)

Q.5 Energy in nt orbit of H-atom is E=-13.6/n ev. What will be the K.E and P.E of an electron in firstexcited state? (2 marks)

Q.6 State two limitations of Bohrs atomic model. (2 marks)

Q.7 Show the graphical variation of potential energy of a pair of nucleons with inter atomic separation.

Also mention the attractive and repulsive region. (3 marks)

Q.8 Draw a schematic arrangement of Geiger-Marsden experimental setup. How does it explain the sizeof nucleus. (3 marks)

Q.9 The energy levels of an atom are given below. Which of them will results in emission of photon275nm? (3 marks)

Q.10 For a photosensitive surface threshold wavelength is 0.Does photo emission occur if wavelength() of incident radiation is more than 0, less than 0. Justify your answer. (2 marks)


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Q.11 The ionization potential of H-atom is 13.6ev. What will be its energy in n=2 state?(1 mark)

Q.12 Will neutron to proton ratio increase or decrease in a nucleus when an electron is emitted? (1mark)

Q.13 States Bohrs postulate. (2 marks)Q.14 If the intensity of the incident radiation in a photocell is increased. How does the stopping potential

vary? (1 mark)

Q.15 Name the series of H-atom spectrum which has least wave length. (1 mark)

Q.16 How did the debroglie equation lead to the quantization condition laid down by Bohr ? (2 marks)

Q.17 Two nuclei have mass numbers in the ratio 2:5 what is ratio of their nuclear densities? (1 mark)

Q.18 What are thermal neutrons? (1 mark)

Q.19 A proton and an alpha particle are accelerated through the same potential .Which one them has

Higher De Broglie wave length. (3 marks)

Q.20 What is the significance of negative energy of an electron in nt orbit of atom?(1 mark)

Q.21 Calculate the energy released in MeV in the following nuclear reaction

12U238

90th234

+ 2He4+ Q

M(92U) = 238.05079U, M(90th) = 234.043630u, M(2He4) = 4.0026ou (2 marks)

Q.22 State Einsteins Photoelectric equation. (1 mark)

Q.23 Compare the radii of two nuclei of mass number 1 & 27? (1 mark)

Q.24 When a monochromatic yellow colored light beam is incident an a given photosensitive surface,

photo electrons are not ejected to green colored monochromatic beam.What will happen if the same surface is exposed to (i)violet and (ii) red colored monochromaticbeam of light. (2 marks)

Q.25 X-rays of wavelength fall on the photosensitive surface emitting electrons. Assuming that thework function of the surface can be neglected , Show that De Broglie wave length of electrons

emitted will be . (5 marks)

Q.26 Name the four essential components of a nuclear reactor. (2 marks)

Q.27 Explain the effect of increase of intensity and potential difference on photoelectrons kinetic energy.

Q.28 Calculate the number of photons emitted per second by transmitter of 10 KW power; radio waves offrequency 6105Hz. (2 marks)

Q.29 Explain the term chain reaction what are the functions of moderator & control rods in nuclear

reactor. (3 marks)

Q.30 The value of ground state energy of H-atom is -13.6ev. (2 marks)

(i) What does the negative sign signify

(ii) How much energy is required to take an electron from the ground state to the first excited state.

Q.31 Define half life period and decay constant of radioactive substance. Write the S.I. units. (2 marks)

Q.32 Compare the radii of two nuclei with mass number 1 & 27 respectively. (1 mark)


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Q.33 Calculate the shortest wavelength of Lyman series of H-atom spectrum. (2 marks)

Q.34 Name the series of H-atom spectrum which lies in visible region? (1 mark)

Q.35 The energy level diagram of an atom of an element is given below. Identify by doing necessarycalculation, which transition corresponds to the emission of a spectral lines of wave length

102.7nm. (3 marks)

Q.36 The radius of the inner most electronic orbit of a hydrogen atom is 5.3 x 10-11m. What are radii ofthe n=2 & n=3 orbits? (2 marks)

Q.37 State the Bohrs postulate. Using it deduce an expression for radius and energy of an electron on H-atom. (5 marks)

Q.38 Write the nuclear decay process for decay of ? (1 mark)

Q.39 A neutron is absorbed by 3 Li nucleus with the subsequent emission of an -particle. Write thecorresponding nuclear reaction. Calculate the energy released in Mev in this reaction

Given mass(3Li)=6.01512126u, M(10n)=1.0086654u, M(2He4)=4.0026044u and M(1H

3) =

3.010000u. (3 marks)Q.40 The energy of an atom of an element X is shown. A photon of wave length 620nm is emitted. Which

one transition is possible? (3 marks)

Q.41 Deduce an expression for energy of an electron in H-atom in nth orbit. (5 marks)

Q.42 The wavelengths of some of the spectral lines obtained in H-atom spectrum are 9546Ao,6463Aoad1216A

o.which one of these wavelengths belongs of Lyman series? (1 mark)

Q.43 The electron in a given Bohr orbit has total energy of -1.5 ev. Calculate the K.E & P.E. in this orbit.(2 marks)

Q.44 Draw a plot showing the variation of binding energy per nucleon versus the mass number A. Explain

with the help of this plot the release of energy in the processes of nuclear fission & fusion. (3

marks)

Q.45 The binding energy of an electron in the ground state of he is 24.6ev . what is the energy required toremove both electrons? (2 marks)

Q.46 In an experiment on photoelectric effect , the following graph were obtained. Name the

characteristics of incident radiation that was kept constant. (1 mark)

Q.47 Draw a schematic diagram of the experimental arrangement used by Davisson & Germer toestablish wave nature of electrons .Explain briefly how the De Broglie relation was verifiedexperimentally. (3 marks)

Q.48 Complete the nuclear reaction 2He4+ 4Be

9 + - - - - - - - - ? (1 mark)

Q.49 A Source of light is placed at a distance of 50 c.m from a photocell and cutoff potential is found tobe Vo .If the distance b/w source and photocell is made 25 c.m. What will be new cutoff


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PHYSICS ASSIGNMENT

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potential. (2 marks)

Q.50 An electron and a proton have same De broglie wavelength associated with them. How are theirKinetic energies related to each other ?

Q.51 The wavelength of a photon and De Broglie wavelength is of an electron have the same value

.Show that energy of photon is 2 mc/n times the energy of the electron. (2 marks)Q.52 Deduce the Bohrs quantization on the basis of debroglie concept. (3 marks)

Q.53 Draw the energy spectrum lines for H-atom. Calculate the frequency of photon which can excite theelectron to -3.4ev from -13.6ev. (5 marks)

Q.54 Derive an expression for the de Broglie Wavelength of an electron moving under potentialdifference of V volt. (2 marks)

Q.55 An electro magnetic wave of wave length is incident on a photosensitive surface of negligiblework function .if photoelectrons emitted from this surface have the De Broglie wavelength 1them

show that . (3 marks)

Q.56 With what purpose was famous Davisson - Germer experiment with electrons per formed ? (1mark)

Q.57 What does Rutherford scattering experiment prove? (1 mark)

Q.58 Two radioactive nuclei X & Y initially contain an equal number of atoms. Their half life is 1 hourand 2 hour respectively. Calculate the ratio of their rates of disintegration after two hours. (2marks)

Q.59 Calculate the binding energy per u nucleon of 17Cl . (3 marks)

Given mass of 17Cl35

= 34.980000u, M(1H1) = 1.007825u and M(0n

1) = 1.008665u

Q.60 Draw a graph showing the variation of potential energy of a pair of nucleon & as a function of their

separation. Indicate the regions in which nuclear force is attractive and repulsive. (3 marks)

Q.61 Sketch a graph b/w ? of incident radiation and stopping potential for a given photosensitive material.What information can be drawn from the value of intercept on the potential axis. (5 marks)

Q.62 The electron in a Bohr orbit has total energy of -1.5ev calculate (i) K.E (ii) P.E (iii) wavelength oflight emitted when electron makes transition to the ground state. In which region does it belong?

(5 marks)

Q.63 Write limitation of Rutherford atomic model? (1 mark)

Q.64 A radioactive nucleus is represented by the symbol bZa. How is the new nucleus is represented after

the emission of (i) an -particle (ii) a beta particle (iii) ray. The activity of source undergoing a

decay is No at t = 0. Obtain an expression for Half Life Time in terms of activity N at anysubsequent time t. (5 marks)

Q.65 IF the frequency of incident radiation an photocell is doubled for same intensity ,what charges willyou observe in. (3 marks)

(i) Kinetic energy of photo electrons

(ii) Photoelectric current

(iii) Stopping potential.

Q.66 Calculate the energy released m mev in following reaction

92U238

----> 90th + 2He4+ Q


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M(92U) = 238.05079U, M(Th)=234.043630U, M()=4.002600U,

Also estimate the energy of emitted particle. (3 marks)

Q.67 Calculate the maximum kinetic energy of particle emitted during -decay of

92U238

90Th234

+ 2He4

M(92U238) = 238.05079U, M(90Th

234) = 234.04363U, M(2He4) = 4.00260U (3 marks)

Q.68 (a) Explain with the help of suitable nuclear reaction in each of the following case how neutron

proton ratio changes during decay & decay

(b) Define actively of a radioactive sample give its S.I unit. (5 marks)

Q.69 The stopping potential in an experiment in Photoelectric effect is 1.5 eV. What is the maximumkinetic energy of the photoelectron. (1 mark)

Q.70 Ultra violet light of wavelength 2271 Aois incident on two photo sensitive material having workfunction W1 and W2(W1 >> W2). In which case will the kinetic energy of emitted electrons begreater ? (1 mark)

Q.71 Show that nuclear density of matter in nuclei is independent of mass number A. (2 marks)

Q.72 The ground state energy of H-atom is -13.6ev. If an electron makes a transition from energy level -0.85ev to -3.4ev. Calculate the wavelength of spectral line emitted to which series of H-atomspectrum does this belong ? (3 marks)

Q.73 (a) Show that the decay rate r of a sample of a radionuclide is given as R = N.

(b) The half life of 92U238

against -decay is 1.5 x 1017

s. what is the activity of a sample of 92U238

having 25 x 1020atoms. (5 marks)

Q.74 The frequency of incident radiation is greater than threshold frequency 0 in a photocell .Howwill the stopping potential vary if frequency is increased. (1 mark)

Q.75 How is the half life of radioactive substance related to its decay constant? (1 mark)

Q.76 Show the graphical variation of photocurrent with intensity of incident radiation at constant potentialdifference b/w electrons and the graphical variation of photocurrent of incident radiation. (3marks)

Q.77 Show the graphical variation of stopping potential with the frequency of incident radiation .How dowe determine the Plancks constant using Graph. (2 marks)

Q.78 With the help of an example, explain how the neutron to proton ratio changes during decay ofnucleus? (2 marks)

Q.79 A radioactive nucleus A undergoes a series of decays according to the following scheme

The mass number and Atomic number of A4 are 172 & 69 respectively what are these numbers forA. (2 marks)

Q.80 Give example of decay. (1 mark)

Q.81 Draw the energy spectrum lines of H-atom. (3 marks)

Q.82 Draw the Binding energy curve showing the variation of BEN with mass number. (2 marks)


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Q.83 How does the maximum kinetic energy of photoelectrons vary with work function of metal ? (1mark)

Q.84 Name two essential components of nuclear reactors. (2 marks)

Q.85 Two metals P and Q have work function 2ev and 4ev respectively. Which of the two metal have

smaller threshold wavelength. (1 mark)Q.86 States laws of radioactive decays. (2 marks)

Q.87 Complete the following nuclear reaction (2 marks)

Q.88 State the laws of Photoelectric effect. Explain it on the basis of Einstein equation. (3 marks)

Q.89 Draw a schematic arrangement of Geiger-Marsden experiment? (2 marks)

Q.90 Two lines A and B in the plot given below show the variation of De Broglie wavelength versus 1/

. Where V is the accelerating potential difference for two particles carrying the same charge

.Which one represents a particles of smaller mass. (2 marks)

Semiconductor Electronics MaterialsQ.1 Why is frequency modulation is preferred over Amplitude modulation in music transmission? (1

mark)

Q.2 Explain the function of Repeater in communication system. (2 marks)

Q.3 Explain how original message will be received at the receiver end. (3 marks)

Q.4 A schematic arrangement for transmitting a message signal (20 Hz. To 20 KHz) is given below.Give two draw back from which this arrangement suffers. Draw the corrected diagram. (3 marks)

Q.5 Why is ground wave is not used for long distance communication ? (1 mark)

Q.6 Why do we require modulation? Explain the AM with block diagram. (3 marks)

Q.7 What is sky wave propagation? (1 mark)

Q.8 By what percentage will the transmission range of T.V. tower be affected when height of distance isincreased by 21 %. (2 marks)

Q.9 Explain the term side band frequency, Band width of signal. What will be the Band width of signalused for music and T.V. broadcast? (3 marks)

Q.10 Write two factors justifying the need of modulation for transmitting the signal. (2 marks)

Q.11 A message signal of frequency 15 KHz. and peak voltage of 5 volts is used to modulation a carrierof frequency 1 MHz . and peak voltage 20 volt .Determine the modulation index and the sidebands. (2 marks)

Q.12 Name the modulation in speech transmission. (1 mark)Q.13 What should be length of antenna for a carrier wave of frequency 6 10

8Hz? (1 mark)


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PHYSICS ASSIGNMENT

Q.14 Explain the term Attenuation. (1 mark)

Q.15 Explain the terms: Space and Sky wave. (3 marks)

Q.16 Name the type of communication in which the signal is a discrete and coded version ofinformation. (1 mark)

Q.17 Draw the block diagram of a Transmitter. (2 marks)

Q.18 A T.V tower has a height 400 m. Calculate the coverage range of Radius of earth is 6400 km. (1mark)

Q.19 What is AM? Represent the process graphically. Write its two limitations and two advantages. (3marks)

Q.20 What is the antenna ? (1 mark)

Q.21 Give reason for following: (3 marks)

(i) Long distance radio broadcast use short wave bands.(ii) Satellites are used for long distance TV transmission.

Q.22 What are AM? How AM wave are produced? Explain with the help of block diagram. (3 marks)

Q.23 What type of modulation is required for T.V. transmission? (1 mark)

Q.24 Draw the block diagram of a Receiver. (2 marks)

Q.25 What do you mean by transducer ? (1 mark)

Q.26 Define modulation index .What would be the value of modulation index for No DISTORTION inmessage signal. (2 marks)

Q.27 Why is short wave bend used for long distance radio broadcast ? (1 mark)

Q.28 Draw the block diagram of basic element of communication system. (2 marks)

Q.29 Explain the principle of transmitting signals using a satellite. State two main advantages of satellitecommunication ? (2 marks)

Q.30 What do you mean by LOS. Communication. Write an expression for distance between Receivingand transmitting antenna used for LOS communication. (3 marks)

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Class XII Physics Assignment