1.0: ELECTROSTATICyslphysics.weebly.com/uploads/4/8/2/6/48261583/sep_… · · 2017-02-05Physic’s Unit, KML 1 1.0: ELECTROSTATIC 1 (a) (i) State the units for electrostatic force

Synergizing Excellence Project

Physic’s Unit, KML 1

1.0: ELECTROSTATIC

1 (a) (i) State the units for electrostatic force and electric charge.

(ii) A positive test charge, q is placed near a positive fixed charge, Q. As q

moves away from Q, describe the motion of the test charge in term of

acceleration whether zero, non zero constant, increasing or decreasing.

State your reasoning.

(b)

FIGURE 1

Two equal and opposite charges are a small distance apart, forming an electric

dipole. A positive charge +q is placed above these charges, as shown in

FIGURE 1, equidistant from both of them. Describe all of the forces and the

net force on the charge +q because of the dipole by sketching electric force

diagram.

(c)

FIGURE 2

FIGURE 2 shows two charged particles on an x axis: q =

at x = 3.00 m and q = at x = + 3.00 m.

(i) Calculate the net electric field produced at pointP at y = 4.00 m?

(ii) Calculate electric potential at point P due to the two charges.

(



2 (a) (i) State the relationship between magnitude of electric force that exists on

a point charge due to second point charge with the separation distance

between those point charges.

(ii)

FIGURE 1

Two electrons (e1 and e2) and a proton (p) lie on a straight line, as

shown in FIGURE 1. Describe the directions of the force of e2 on e1,

the force of p on e1, and the net force on e1 by sketching electric force

diagram.

(b) Experiment A uses a test charge q0 and experiment B uses a test charge 2q0 to

measure an electric field produced by a stationary point chargeQ at a location

P near the point charge. By using definition of electric field, determine electric

field at the location P respectively if you carry out both of the experiments A

and B. Compare the result of those experiments A and B.

(c)

FIGURE 2

Points R and T are each a distance d = 0.10 m from each of two particles with

charges of equal magnitudes and opposite signs as shown in FIGURE 2.

Magnitude of the charge is 10 μC. Determine the work required to move a

particle with negative charge q= 2.0μC from R to T. (



2.0: CAPACITOR AND DIELECTRICS

1 (a) (i) If the electric field between the plates of a given air-filled capacitor is

weakened by removing charge from the plates, describe the capacitance

of that capacitor whether increase, decreases or does not change.

Explain your reasoning.

(ii) A certain physical quantity is a measure of how quickly a capacitor

charges or discharges. State that physical quantity and its unit.

(b)

FIGURE 1

(i) Describe the connection between 9.0 pF capacitor and 11 pF capacitor.

(ii) Find the equivalent capacitance between point a and point c.

(c) A resistor is connected in series with a capacitor and a battery

of 12 V. Before the switched is closed at time t=0 s, the capacitor is

uncharged.

(i) Sketch and label a circuit to describe the situation.

(ii) Determine the charge on the capacitor at t=10 s.



2 (a) (i) If both the plate area and the plate separation of a parallel-plate

capacitor are doubled, Explain and describe the capacitance whether

increasing, decreasing or unchanged.

(ii) A dielectric slab is slowly inserted between the plates of a parallel

plate capacitor, while the potential difference between the plates is

held constant by a battery. As it is being inserted, describe the

capacitance and accumulated charge on each plate whether increasing,

decreasing or unchanged.

(b)

FIGURE 2

FIGURE 2 shows six 6 F capacitors. Determine the capacitance between

points a and b.

(c)

FIGURE 3

Total energy of 0.040 J is stored in the two identical capacitors shown in

FIGURE 3 when they are connected with a power supply of 200V. Determine

the capacitance of each capacitor.



3.0: ELECTRIC CURRENT & DIRECT CURRENT CIRCUITS

1 (a)

FIGURE 1

The figure shows a graph of the resistance of a wire as a function of its length.

State the physical quantities does the slope of this graph represent?

(b) A 60.0 Ω resistor is connected in parallel with a 100.0 Ω resistor. This parallel

group is connected in series with a 20.0 Ω resistor. The total combination is

connected across a 15.0 V battery.

(i) Sketch the circuit to describe the situation.

(ii) Determine the current across the 100.0 Ω resistor.

(iii) Determine the power delivered to the 100.0 Ω resistor.

(c)

FIGURE 2

Current which is flowing from point f to e through the 14.0 V battery is

3.0 A. Determine the current which is flowing through point a.



2 (a) (i) Describe the physical properties in terms of thickness, length and

temperature for a copper conductor so that it will have a least

resistance.

(ii) A certain wire has resistance R. Second wire, of the same material, has

half the length and half the diameter of the first wire. Determine the

resistance of the second wire in term of R.

(b) (i)

FIGURE 3

In the FIGURE 3, the current in the 3 resistor is 4 A. Determine the

potential difference between points 1 and 2.

(ii) Four 20 resistors are connected in parallel and the combination is

connected to a 20 V emf device. Calculate the current in any one of the

resistors.

(c)

FIGURE 4

A potentiometer is balanced when position of the jockey is at point c as shown

in FIGURE 4. Determine the length of ac, when galvanometer’s reading is

zero. Given that and length of wire ab is 1.0 m.



4.0 MAGNETIC FIELD

1 (a) Define magnetic field

(b) A particle 8.5mC with velocity 14.75kms initially moving northward is

deflected toward east in a magnetic field1.25T ,

(i) State the direction of magnetic field. Illustrate the diagram by drawing

the direction of magnetic force and velocity.

(ii) Calculate the magnetic force on the particle.

(iii) Calculate the acceleration experienced by the particle given the mass

of the particle is 201.77 10 kg

(c) The springs X and Y, having an original length of 3cm and force constant 3

Nm-1

each, are fixed to two straight insulated wires LM and VW on a smooth

horizontal surface as shown in the figure below. When the switch S is turned

on, a current of 40 A flows through the wires. Calculate

(i) the magnetic force acting on each wire LM and VW

(ii) The distance between LM and VW when the equilibrium is reached.



2. (a) Define 1 ampere.

(b) The magnetic field at the centre of a circular coil of radius 5 cm is 60 T . If the

number of turn of coil is 4, calculate the current flow through the coil.

(c) A heart surgeon monitors the flow of blood through an artery using an

electromagnetic flowmeter as shown in the figure below. The blood is known

to contain mobile positive ions. Electrodes X and Y make contact with the

outer surface of the blood vessel. The separation of the electrodes X and Y is 41.4 10r m . When a magnetic field of flux density 2T is produced by the

electromagnet, a potential difference 600V is developed between the

electrodes X and Y. When this condition is reached, the blood flows only a

certain speed

(i) Calculate the magnitude of the electric force on the ion.

(ii) State the conditions for the blood to flow only at certain speed

(iii) Calculate the speed for the condition given in (ii).

(d) In a moving coil galvanometer ,the coil of 400 turns has a rectangular shape of

dimensions 3cm x 5 cm. The radial magnetic field has a magnetic flux density

of 0.24 T. Calculate the torque on the coil when a current of 0.024A flow in it.



5.0: ELECTROMAGNETIC INDUCTION

1 (a) State Faraday and Lenz law

(b) A long magnet is removed from the centre of a solenoid as shown in the

figure. The coil is connected to a sensitive ammeter. The speed of the magnet

is controlled to maintain an induced e.m.f of 60 V across the coil.

Removing the magnet in this way takes 2 s.

(i) Calculate the change of flux through the coil

(ii) Calculate current flow in the solenoid if the resistance is 2 .

(ii) Explain the way to verify the polarity of the magnet.

(c) A magnetic field B is applied perpendicular to a coil as shown in the figure

below.

(i) Use Faraday’s law to explain briefly how an induced current is

produced in the resistor by reducing gradually the magnetic field.

(ii) Determine direction of the induced current. Explain your answer.



2 (a) (i) Define magnetic flux

(ii) A circular coil with diameter 3 cm is placed in uniform magnetic field

1.5 T. Calculate the magnetic flux through the coil when the plane of

the coil makes an angle of 30 to the magnetic field.

(b) A rectangular coil ABCD of 60 turns has its plane set parallel to a uniform

magnetic field 0.02T as shown in figure .The coil of sides AB and CD are of

length 10cm and side BC is of length 8cm . A current I is flowing through

the coil.

(i) Copy the

diagram

and draw the

direction of

the force

acting on sides

AB and CD

respectively.

(ii) The current I is then switched off and the coil is rotated about an axis

at a constant angular velocity, . Explain why an e.m.f is induced in

the coil.

(iii) Calculate the maximum value of induced emf for the coil given the coil

rotates at 120 rev/min.

(iv) Sketch graphs to show the variation of the magnetic flux linkage

through coil with respect to time.

(c) A coil P with the length of 50cm and radius 3cmhas 1000 turns. The self

inductance of the coil is 0.2 mH. If the current flows through it is 4 A,

calculate the mutual inductance if a coil Q with 50 turns is placed beside coil

P.



6.0: ALTERNATING CURRENT

1 (a) (i) The rms output voltage of an AC source is 200.00 V, and the operating

frequency is 100.00 Hz. Write the equation for the output voltage as a

function of time.

(ii) At what frequency does the inductive reactance of a 57.00 μH inductor

equal to the capacitive reactance of a 57.00 μF capacitor?

(b) A 50.00 Ω resistor, a 0.10 H inductor and a 100.00 µF capacitor are connected

in series to a 60.00 Hz AC source. The rms current in the circuit is 2.75 A.

Find the rms voltage across

(i) the resistor

(ii) the inductor

(iii) the capacitor

Sketch the phasor diagram for the circuit.

(c) To determine the inductance of a coil used in a research project, a student first

connects the coil to a 12.00 V battery and measures a current of 0.63 A. The

student then connects the coil to an AC source of Vrms = 24.00 V, f = 60.00 Hz

and measures an rms current of 0.57 A. What is the inductance of the coil?

2 (a) Is the sum of the voltages across the elements in a series RLC circuit greater

than or less than the applied voltage? Explain.

(b) An AC source with Vmax = 150.00 V, f = 50.00 Hz is connected between points

a and d as shown in the figure below.

Calculate the maximum voltage between points

(i) a and b

(ii) b and c

(iii) c and d

(iv) b and d

(c) An AC voltage in the form of 100 sin 1000V t is applied to a series

RLC circuit . If R = 400.00 Ω, C = 5.00 μF and L = 0.50 H, calculate

(i) the average power delivered to the circuit

(ii) the power factor of the circuit



7.0: GEOMETRICAL OPTICS

1 (a) (i) In a Jules Verne’s novel, a piece of ice is shaped into a magnifying

lens to focus the sunlight to start a fire. Is this possible?

(ii) A ball is dropped from rest 3.00 m directly above the vertex of a

concave mirror that has a radius of 1.00 m and lies in a horizontal

plane. At what time do the ball and its image coincide?

(b) A concave spherical mirror has a radius of curvature of 20.00 cm. Find the

location of the image for the object distances of

(i) 40.00 cm

(ii) 20.00 cm

(iii) 10.00 cm

For each case, state whether the image is real or virtual and upright or

inverted, and find the magnification.

(c) At an intersection of hospital hallways, a convex mirror is mounted high on a

wall to help avoid collisions. The mirror has a radius of curvature of 0.55 m.

Locate and describe the image of a patient 10.00 m from the mirror.

2 (a) A simple model of the human eye ignores its lens entirely. Most of what the

eye does to light happens at the transparent cornea. Assume that this outer

surface has a 6.00 mm radius of curvature, and assume that the eyeball

contains just one fluid with an index of refraction of 1.40. Prove that a very

distant object will be imaged on the retina, 21.00 mm behind the cornea.

(b) An object positioned 32.00 cm in front of a lens forms an image on a screen

8.00 cm behind the lens.

(i) Find the focal length of the lens.

(ii) Determine the magnification.

(iii) Is the lens converging or diverging? Explain.

(c) A magnifying glass is a converging lens of focal length 15.00 cm. At what

distance from a postage stamp should you hold this lens to get a magnification

of +2.00?

(d) For a biconcave lens, the radii of curvature for the two surfaces are 32.50 cm

and 42.50 cm respectively. The glass has the refractive index of 1.53 for the

violet light. For a very distant object, locate and describe the image formed by

the violet light.



8.0: PHYSICAL OPTICS

1. (a) (i) State Huygens’ principle.

(ii) The figure shows a point light source P on the ground.

Draw the wavefront from point P at time t = 1 s and t = 2 s. Clearly

show the construction that you make and direction of the ray.

(b) A beam of a monochromatic light of wavelength 640 nm passes

through a single slit of width 4.8 x 10-3

mm. The screen is located at a

distance of 0.5 m away from the slit. Determine

(i) the angular width of the central bright fringe

(ii) the width of the central maxima

(iii) the number of bright fringe that can be observed.

2. (a) (i) What is meant by coherent sources?

(ii) Suggest two methods of producing two coherent waves.

(b) Two point sources X and Y emits waves of wavelength 2.0 cm in phase. The

point P is 5.0 cm from X and 8.0 cm from Y. Another point Q is 10.0 cm from

X and 4.0 cm from Y. Determine

(i) the path difference of waves X and Y at the point P

(ii) the path difference of waves X and Y at the point Q

(iii) the type of interference occurs at point P and Q.

(c) In a Young’s double slits experiment to determine the wavelength of

monochromatic light from a source, the following measurements were made.

Separation between two slits = 0.20 mm

Distance of screen from the two slits = 55.0 cm

Distance between the mth and the (m + 10)th bright fringe = 11.4 mm

Determine the wavelength of the monochromatic light.

(d) A beam of light composing of two wavelengths, λ1 and λ2, is used in a

Young’s double slits experiment. It is observed that the 4th dark fringe

produced by λ1 coincides with the 3rd bright fringe produced by λ2 on a

screen. If λ1 has a value of 510 nm, determine the value of λ2.

P



9.0: QUANTIZATION OF LIGHT

1. (a) (i) What is photoelectric effect?

(ii) State four most important results from a photoelectric effect

experiment.

(b) The work function for Cesium is 2.14 eV.

(i) Calculate the maximum wavelength of light that ejects electron from a

Cesium target.

(ii) Determinethe speed of the photoelectrons produced when the Cesium

is illuminated by the light of wavelength from question (i).

(iii) If light of wavelength 452 nm is illuminated on the Cesium, calculate

the maximum kinetic energy of photoelectron.

(iv) What will happen if a light of wavelength 595 nm is illuminated on the

Cesium? Why?

2. (a) What is the energy in electron-volt (eV) of a photon of green light of

wavelength 525 nm?

(b) For a certain cathode material in a photoelectric effect experiment, a stopping

potential of 1.0 V for light of wavelength 750 nm, 2.0V for 500 nm and 3.0 V

for 375 nm.

(i) Plot a V-f graph based on the date given.

(ii) Determine the work function for this material.

(c) A light of wavelength 200 nm falls on nickel with a work function of 5.1 eV.

Determine

(i) the kinetic energy, in electron-volt (eV), of the photoelectrons emiited.

(ii) the stopping voltage.

(iii) the maximum speed of the photoelectrons.



10.0: WAVE PROPERTIES OF PARTICLE

1. (a) (i) State de Broglie’s hypothesis and give the relationship between

momentum and wavelength of a particle.

(ii) In an electron diffraction experiment, an electron beam which is

accelerated on a potential difference is incident normally on a very thin

gold film. If the voltage at the anode is increased, what happens to the

circular ring?

(iii) Give evidence that shows a particle behaves as wave and a wave

behaves as particle.

(b) An electron has a de Broglie wavelength of 1.2 × 10-10

m. Calculate

(i) the momentum of the electron

(ii) the kinetic energy of the electron

(iii) the potential difference required to accelerate the electron.

2. (a) (i) Name two physical differences in the structure of the optical

microscope and the electron microscope.

(ii) Explain the advantage of using an electron microscope.

(b) The potential difference between the cathode and anode of a cathode ray tube

is 3.0 kV. The separation between the anode and cathode is 50 mm. Determine

(i) the speed of the electrons that emerge from the anode

(ii) the time taken by the electrons to travel from the cathode to the anode

(iii) the de Broglie wavelength of the electron beam that emerges from the

anode.

(iv) If the potential difference between the cathode and anode is doubled,

describe quantitatively the change to the de Broglie wavelength of the

electron beam.



11.0: NUCLEUS

1. (a) State three differences between isotopes O16

8 and O17

8 .

(b) An indium (In) nucleus contains 49 protons and 66 neutrons. Write the

element in nuclide form.

(c) Radon, Ra226

88 has atomic mass of 226.02544 u. Calculate

(i) the mass defect in atomic mass unit, u,

(ii) the binding energy in MeV,

(iii) the binding energy per nucleon.

Given :mp= 1.007277 u; mn = 1.008665 u

(d) Figure below shows a graph of binding energy per nucleon against nucleon

number.

(i) From the graph, determine the binding energy per nucleon if a nucleus

has nucleon number is 80.

(ii) Using your answer from d)(i), calculate the binding energy of the

nucleus.



2. (a) For neutral atoms, how many

(i) protons are in the U238

92

(ii) neutrons are in the Hg202

80

(b) The nuclear mass of Copper-63 is 62.91367 u.

(i) Determine the mass defect in atomic mass units (u) and kilograms (kg)

for copper which has 63 nucleons and a proton number of 29.

(ii) Calculate the binding energy of the Copper-63 nucleus in MeV.

(iii) Calculate the binding energy per nucleon of the Copper-63 nucleus.

Given :mp= 1.007277 u; mn = 1.008665 u

(c) Figure below shows a graph of binding energy per nucleon against

mass number.

Explain briefly about the stability of following nuclei:

(i) Hydrogen-2 (2H)

(ii) Nickel-62 (62

Ni)

(iii) Uranium-238 (238

U)



12.0: NUCLEAR REACTION

1. a) Nuclear energy can be produced by the following equation:

QnHeXH 1

0

3

2

2

1

(i) Identify the element X.

(ii) State whether the equation is fusion or fission reaction.

Justify your answer.

(iii) Calculate the amount of nuclear energy, Q released.

Given: mp= 1.007277 u; mn = 1.008665 u; mH = 2.014102 u;

mHe = 3.016029 u

b) The nuclear equation shown below represents the decay of radium

to radon with the release of energy.

HeRnRa 4

2

222

86

226

88

Given: 226

Ra = 226.02544 u;

222

Rn = 222.01761u;

4He= 4.002603 u

(i) Give a reason why radon (Rn) is more stable than radium (Ra).

(ii) Calculate the mass defect, in kg, for this reaction.

(iii) Calculate the energy released in this reaction.

(iv) Calculate the mass of radium (in kg) required to release 2000 MJ of

energy.



2. a) State conservation of charge (Z) and nucleon number (A) in a nuclear reaction.

b) A reaction of nuclear fission is represented by the following equation.

energy1

0

93

37

141

55

1

0

235

92 nXRbCsnU

(i) Use the equation to determine the value of X.

(ii) Calculate the mass loss of the above reaction.

(iii) One atomic bomb uses 100 kg of U-235. Determine the reduction in

mass which occurs if all of U-235 undergo fission.

(iv) How much energy is released in the fission of U-235 in (iii)?

Given :235

U=235.04392 u; 141

Cs=140.91963 u; 93

Rb; mn=1.008665 u

c) Name two of the form of energies released during nuclear fission.

d) State three differences between nuclear fission and nuclear fusion reaction.



13.0: RADIOACTIVITY

1 (a) ‘Radioactivity is a random process.’ Explain what is meant by a random

process in this context.

(b) A sample of uranium-238 contains 2.50 × 1023

atoms. Given that the half-life

of uranium-238 is 1.42 × 1019

s, find

(i) the decay constant,

(ii) the initial activity of the sample, in Becquerel,

(iii) the number of uranium-238 atoms remaining after 3.0 × 1018

s.

(c) Induced radioactive technetium is often used as tracers in medical

diagnoses. It has a half-life of 6.0 hours.

(i) Determine the mass of technetium which is required to produce a

sample of activity 3.7 x 106 decays s

-1.

Given: mass of one mole of technetium is 99.43 g

(ii) Besides technetium, give one example of radioisotope used as

radioactive tracer in medicine and its application.



2. (a) Write decay equations for β emission from a Co60

27 nucleus to produce Nickel

(Ni).

(b) A smoke detector contains a small radioactive source. A typical source

contains 1.2 × 10–8

g of americium-241, which has a half-life of 432 years.

(i) Determine the decay constant of americium-241.

(ii) Calculate the number of nuclei in 1.2 × 10–8

g of americium-241, given

that 241 g contains 6.02 × 1023

nuclei.

(iii) Hence, calculate the activity of 1.2 × 10–8

g of americium-241.

c) Nuclear-powered electronic pacemakers were sometimes used to regulate the

heartbeat. Such pacemakers were used inside the body and were powered by a

small radioactive source.

One type of pacemaker used an isotope of plutonium, Pu-238, as its energy

source.Pu-238 decays by an alpha emission with a half-life of 88 years.

(i) Complete the equation for plutonium decaying into thorium.

Th Pu238

92

(ii) The activity of the source in one such pacemaker, when the pacemaker

was fitted, was 9.3 × 1010

Bq. The energy released by each alpha decay

is 5.5 MeV.

Calculate the power of the source 30 years after fitting.

Documents

1.0: ELECTROSTATICyslphysics.weebly.com/uploads/4/8/2/6/48261583/sep_… · · 2017-02-05Physic’s Unit, KML 1 1.0: ELECTROSTATIC 1 (a) (i) State the units for electrostatic force