KAKAMEGA COUNTY JOINT EVALUATION EXAM Kenya...

KAKAMEGA COUNTY JOINT EVALUATION EXAM

Kenya Certificate of Secondary Education ( K.C.S.E)

232 /1

PHYSICS

Paper1

July / August 2013 SECTION A (25 MARKS)

1. The figure below shows the face of an ammeter indicating a current. Given that this ammeter has zero error of

0.02A, state the value of the current indicated. (2 marks)

2. The figure below shows a lorry on an inclined section of a straight road. At the back is a chain hanging from a

point on a horizontal axis through the centre of gravity of the lorry.

State with a reason whether the lorry is stable or not stable. 91 mark)

3. The figure below shows a rod made of wood on one end and metal on the other end. It is suspended freely with a

piece of thread so that it is at equilibrium.

The side of metal is now heated with a Bunsen burner flame and the rod tilts to the left. Explain. (2 marks)

4. A certain solid of volume 80cm3 displaces 80cm3 of a liquid of density 6.50g/m3 when floating. Determine the density of the

solid. (3 marks)

5. Two solid cuboids A and B of equal masses are placed on a uniform metre rule at its centre as shown.

State and explain the observations made. (2marks)

6. A steel sphere released in a tall transparent water jar attains a constant velocity after a while. The same sphere released in air

falls at a constant acceleration. Explain with a reason the difference in its motion in water and in air. (2marks)

7. The figure below shows a syringe full of water. It has two identical holes A and B drilled along its cylinder. The cylinder

nozzle is closed.

When the piston is pushed into the cylinder jet, water of equal speed come out of the holes A and B. Explain (2marks)

8. Explain why a hole in a ship near the bottom is more dangerous than near the surface. (1 mark)

9. A turntable of radius 10cm is rotating at 50 revolutions per second. Determine the linear speed of point on the

circumference of the turntable.

10. When heating water for bathing, it is observed that bubbles form at the bottom of the sufuria and rises to the surface: Explain:

(i) What is contained in the bubble? (1mark)

(ii) Why the bubble rises to the surface of the sufuria? (1mark)

(iii) Why the volume of bubble increases as it rises. (l mark)

11. A bullet of mass 10g is travelling at a speed of 400m/s hits a tree trunk. It penetrates the trunk and stops inside the trunk after

4cm.

a) Calculate the average resistance force offered by the tree trunk to the bullet. (3marks)

b) State the energy changes that take place. (1 mark)

SECTION B (55 MARKS)

Answer all questions in this section

12. a) What is meant by specific latent heat of vaporization? (1 mark)

b) In an experiment to determine the specific latent heat of vaporization of water, steam at 100oC was passed into water

contained in a well lagged copper calorimeter.

The following measurements were made:

Mass of calorimeter = 50g

Initial mass of water = 70g

Initial temperature of water = 50C

Final mass of water + calorimeter + condensed steam = 123g

Final temperature of mixture = 30oC

Specific heat capacity of copper =4200Jkg-1K-1

Specific heat capacity of copper = 390Jkg-1K-1

Determine the:

i) Mass of condensed steam. (1 mark)

ii) Heat gained by water and calorimeter. (2marks)

c) Given that L is the specific latent heat of vaporization of steam.

i) Write an expression for the heat given out by steam

ii) Determine the value of L.

d) 500g of water at 20°C is mixed with 200g of water at C: Find the final temperature of the mixture. (3marks)

13. a) A body in a uniform circular motion experiences acceleration despite having constant speed. Explain. (1 mark)

b) A car travelling with uniform speed on a level circular path is likely to experience skid. Explain

c) The figure below shows a 40g wooden block whirled with uniform speed in a horizontal circular pat radius 20cm. If it

takes 0.5 seconds to describe an arc of length 12cm;

i) Identify the forces acting on the wooden block

ii) Determine the linear velocity of the block. (2mark

iii) Determine the centripetal force.

14. a) Two identical containers A and B are placed on a bench, container A filled with oxygen gas and S with hydrogen gas such

that the two gases have equal masses. If the containers are maintained at the same temperature, state with reason the

container in which pressure is higher. (2marks)

(b) The figure below shows a set-up of an experiment used to investigate Charles's law.

(i) Name the parts marked X and Z .

(ii) State the measurements to be taken in this experiment. (2marks)

(iii) Explain how the reading taken in(ii) above may be used to investigate Charles’ law. (2marks)

(iv) State the two purposes of the mercury index. (2marks)

(c) A constant mass of hydrogen gas occupies a volume of 4.0cm3 at a pressure of 2.4 x 105 Pa and temperature

of 288K. Find its volume at a pressure of 1.6 X. 105 Pa when the temperature is 293K. (3marks)

15. (a) Distinguish between velocity and speed. (1 mark)

(b) The velocity-time graph in the figure below illustrates the motion of a ball which has been projected vertically upwards

from the surface of a planet. The weight of the ball on earth is 30N.

(c) Determine the weight of a ball on the planet,

(d) The figure below shows a section of a tape from ten tick timer whose frequency is 50Hz.

Calculate;

(i) The average velocity of the trolley between points:

1. WX (2marks)

2. YZ (2marks)

(ii) Find the acceleration of the trolley. (2marks)

16. (a) State Hooke's law. (1 mark)

(b) The figure below shows the variation of force with extension for a steel coil spring.

i) In the same diagram, sketch the variation of force with extension for a wire from which the spring is made. (1mark)

ii) Explain the difference between the two lines drawn.

(c) A stone of mass 5g is released from a catapult. The catapult is stretched by 10cm. If the constant of

elasticity is 100N/cm. Calculate:

i) The horizontal velocity with which the stone is released, (2marks

ii) Sketch the graph of horizontal velocity against time from the time the stone is released until it reaches the

ground.

(d) The following results were obtained in an experiment to verify Hooke's law when a spring was extended

by hanging various loads on it.

Load (N) 0.00 1.00 2.00 3.00 4.00 5.00 6.00

Length of spring in cm 10.00 11.50 13.00 14.50 16.00 18.00 24.00

Extension 0.00

i) Complete the table for extension (e) above.

ii) Plot a graph of load y-axis against extension.

iii) From the graph determine the spring constant, K. (2 marks)

iv) Calculate the energy stored when the spring is stretched to 16cm.

KAKAMEGA COUNTY JOINT EVALUATION EXAM

Kenya Certificate of Secondary Education ( K.C.S.E)

232 /2

PHYSICS

Paper2

SECTION A (25 MARKS)

Answer All questions in this section in the spaces provided

1. The diagram below shows an object O placed in front of a plane mirror

Draw rays to locate the position of the image as seen by the eye E through the mirror.

2. The diagram below shows a soft iron ring placed between the poles of a magnet.

Sketch the magnetic field pattern produced (2mks)

3. State the property of x-rays that make it possible to detect cracks in bones (1mk)

4. The audible frequency range of a normal person ranges between 30Hz and 19,500Hz. Determine the largest

wavelength of sound waves in air that this person can detect. (Speed of sound in air = 340m/s). (3mks)

5. Briefly explain how polarization can be overcomed in a simple cell

6. A ray of light is incident on a glass - air medium. Determine the angle of refraction in air for which the angle

of incidence in glass is 33°. (Refractive index of glass = 1.33) (3mks)

7. Arrange the following electromagnetic waves in order of increasing frequency; Visible light: Gamma rays;

Ultraviolet rays and Microwaves (lmk)

8. You are provided with an a.c power supply, 4 diodes, a resistor a CRO and connecting wires. Sketch a circuit

diagram showing how the 4 diodes can be used for full wave rectification of the alternating current as seen on

the CRO. (3mks)

9. A circuit consists of a battery, a metal wire, an ammeter and a switch connected in parallel. The switch is closed

and the ammeter reading noted. The metal wire is then heated while still connected to the circuit.

State and explain the observations made on the ammeter reading. (3mks)

10. The circuit below shows a student's work in an attempt to wire three lamps in a household using three switches.

(i) Briefly explain why this is a poor connection. (2mks)

(ii) Redraw the circuit diagram with the right connection. (l mk)

11. Calculate the angle between two plane mirrors when five images are formed. (2mks)


Answer all questions in this section in the spaces provided

12. a) State Faraday's Law of electromagnetic induction. (1 mk)

b) Describe a simple experiment to demonstrate Faraday's Law. (4mks)

c) An Armature composed of turns of insulated copper wire wound on a soft iron core is rotated in a

magnetic field to produce an e.m.f.

(i) Other than the speed of rotation, state two other factors that affect the magnitude of the generated

e.m.f (2mks)

(ii) Briefly explain why the soft iron is laminated. (2mks)

(d) A transformer with 500 turns in the primary and 50 turns in the secondary is connected to 240V a.c

mains. If a 50 resistor is connected to the secondary coil, determine the energy dissipated by this

resistor if the transformer is 100% efficient. (3mks)

13. (a) State one condition necessary for Ohms Law to be obeyed. (1mk)

(b) You are provided with the following set of resistors; 3 4 and 6. Draw a circuit diagram that can

give an effective resistance of 5.4 (2mks)

(c) The diagram below shows four resistors connected together in circuit.

Determine;

(i) The ammeter reading (4mks)

(ii) The Voltmeter reading (3mks)

14. (a) Define the term Photoelectric effect (lmk)

(b) The table below shows the relationship between the wavelength of a radiation falling on a surface and the

energy E of the emitted electrons.

(i) Complete the table for values of 1

(x 106) giving your answers to 1 dp (3mks)

(ii) Plot a graph of energy E against 1

(5mks)

(iii) Use the graph to determine the Planks constant (h) and the work function Wo of the metal used given that the

equation of the graph is such that:

E = h𝐶

- Wo (Take speed of light c = 3.0 x l0 m/s (4mks)

15. (a) An object placed in front of a concave mirror forms a virtual image with a magnification of 2. If the distance between

the objects and the image is 30cm, determine the focal length of the mirror (4mks)

(b) Define the term Radioactive decay.

(ii) Cobalt a radioactive isotope has a half-life of 5.25 years. Calculate the fraction of the original atoms that will have

decayed after 21 years.

(iii) Two samples of the same radioactive material have masses of M and 2M respectively. Sketch the graph of activity

against time for each sample on the axis provided labeling each sample (2mks)

16. (a) State two factors that affect the capacitance of a parallel plate capacitor. (2mks)

(b) The figure below shows a circuit consisting of resistors and capacitors connected together.

Determine;

(i) The charge stored by the 60𝜇 capacitor when the switch is open. (4mks)

(ii) The charge stored by the 100𝜇 capacitor when the switch is closed. (4mks)

Time (s)

Activity

KAKAMEGA COUNTY JOINT EVALUATION EXAM,

Kenya Certificate of Secondary Education (K.C.S.E)

232 /3

PHYSICS

Paper 3 (Practical)

July / August 2013 1. You are provided with the following apparatus:

- A biconvex lens

- A plane mirror

- A retort stand and clamp

- A supply of water

- A 50mm x 10mm edge

- A millimeter scale along the 10mm edge.

- Two pieces of wood

a) Clamp the two pieces of wood so that they hold the object card horizontally with the calibrated sides upwards.

b) Place the plane mirror on an horizontal surface directly below the object card and place the lens at the centre of

the mirror. See diagram below.

c) Measure a height h, where h = 20cm measured from the surface of the mirror.

d) Keeping your eye about 0.5m from the mirror, adjust the position of the mirror and lens so that you can see an

image of the card in the central region of the lens.

e) By means of a millimeter scale on the top side of the object card, determine the width b, of the image.

f) Repeat the experiment to obtain a series of corresponding values of h and b. Record the results in the table below.

NOTE

(Invert the card for the images larger than the object so that the calibrated side faces the mirror).

Determine the image width by relating to the object width.

TABLE 1

h (cm) 15 17.5 20 22.5 25 27.5

b (cm)

g) On the grid provided, plot a graph of width b against height h (4mks)

h) Remove the lens and put a few drops of water in the center of the mirror. Replace the lens on top of the water so

that the water fills the central region of the lens.

i) Repeat step (e) to obtain a series of corresponding values of h and new image widths w. Record the results in the

table below.

TABLE 2

h (cm) 21 23 25 30 33 36

b (cm)

j) Using the same axes in (g) plot a graph of width w against height h (4mks)

From the graph determine;

(i) hb the value of h when b = 30mm

hb = (1mk)

(ii) hw the value of h when w = 3.0mm

hw = (1mk)

k) Determine the constant k for the water from the expression (2mks)

K = 2 - hb

hw

2. You are provided with the following apparatus:

6 connecting wires, one having a jockey or crocodile clip attached to one end.

A voltmeter (0.3 volts)

A dry cell in a cell holder

A switch

1m constantan wire (SWG 28) fixed on the bench using cello tape with the ends labelled AB.

A meter rule.

Proceed as follows

Set up the circuit as shown below

(a) i) Place the jockey on AC so that the length marked L is 90cm

ii) With the switch open, record the value of the voltmeter reading V1: V1 =

iii) Now close the switch and read the new value of the voltmeter reading V2 when L = 90cm and record it in

the table below.

L (m) 0.60 0.50 0.40 0.30 0.20 0.1

V2

P (Volts)

𝟏𝒑⁄ (V-1)

iv) Repeat part (iii) above for the values of L indicated in the table above

v) Complete the table above for values P where P = V1 - V2 (1mk)

vi) Work out the values of 1 𝑝⁄ and fill in the table. (2mks)

(b) On the grid provided, plot a graph of 1 𝑝⁄ (y - axis) against L (5mks)

(c) The relationship between P and L is given by the equation

1𝑝⁄ = 12

𝑁⁄ - 𝑄𝐿

100 ⁄ where Q and N are constants

Using your graph determine the values of:

(i) Q (3mks)

(ii) N (2mks)

UGENYA / UGUNJA DISTRICTS JOINT EVALUATION TEST, 2013


232 / 1

PHYSICS

Paper 1

(Theory)

July / August 2013

SECTION 1: (25 Marks)

Answer all questions from this section in the spaces provided.

1. Figure 1 shows a vernier calliper being used to measure the diameter of a cylindrical metal of mass 18g and length 20cm.

The reading of the calliper when the jaws were fully closed was -0.11cm. Use this information and the figure to answer

question 1 and 2.

Fig. 1

What is the diameter of the cylindrical metal? (1 mark)

2. Determine the density of the cylindrical metal. (2 marks)

3. Figure 2(a) shows a table tennis ball hanging closely to a water tap. When the tap is opened so that the water flows, the ball is

attracted to the stream as shown in figure 2(b)

Explain the observation. (2 marks)

4. Two candles, a short and a long candle were lit and then covered with a tall bell jar as shown in figure 3 below.

State and explain which of the candles would go off first.

5. a) State the Pascal’s principle. (1mark)

b) If the cross-sectional area of the output piston in a hydraulic device is ten times that of the input piston area, by how much

will the device multiply the input force? (1mark)

6. A bag of sand is found to have the same weight on planet earth as an identical bag of cotton on planet Jupiter.

Explain why the masses of the two bags must be different? (2marks)

7. Two samples of bromine vapour are allowed to diffuse separately under different conditions. One in vacuum and

the other in air. State with a reason the condition in which bromine will diffuse faster. (2marks)

8. Figure 4 below shows glasses resting on an inclined plane. One glass is empty while the other is filled with

water.

Which glass is more unstable and will topple? Explain. (2marks)

9. An air bubble expands as it rises to the surface of water in deep pond. State the cause of this given that the

Temperature remains constant. (1mark)

10. Figure 5(a) shows the momentum- time graph for a certain motion.

Fig 2(b) Fig 2(a)

Fig 5(a) Fig 5(b)

On the axes provided in figure 5 (b), sketch the acceleration time graph for the same motion. (1mark)

11. A uniform half metre rule is supported by force of 3N and 2N as shown in figure 6 below.

Determine the weight of the half metre rule. (2marks)

12. Figure 7 below shows a solid sphere moving on a platform 5m above the ground. It rolls down a curved frictionless path in a

point 0.5m above the ground.

Fig 7

Calculate its velocity at the lower end. (3 marks)

b) A girl swings back and forth on a swing whose ropes are 4.0m long. The maximum height she reached is 2.0m

above the ground. A t the lowest point of the swing she is 0.50m above the ground. What is the girl’s maximum

speed and where does she attain it? (3marks)

c) An oil drop of average diameter 0.7mm spreads out into a roughly circular patch of diameter 75cm on the

surface of water in a trough. Calculate the average diameter of an oil molecule. (3marks)

16. a) State Charles’s law for an ideal gas. (1mark)

b) The figure below shows a type of constant volume gas thermometer.

Describe how it operates. (3marks)

c) The graph below shows the relationship between the product of pressure and volume (PV) and the absolute

temperature for a given mass of gas. From the graph determine:

The pressure necessary for 40 litres of the gas to attain a temperature of 00C (2marks)

17. a) State any form of energy. (1mark)

b) An electric crane lifts a load of 2000kg through a vertical distance of 3.0m in 6 seconds. Determine:

i) The work done (2marks)

ii) The power developed by the crane. (2marks)

iii) The efficiency of the crane if it is operated by an electric motor rated at 12.5KW. (2marks)

c) The figure below shows an ideal displacement time graph for the journey of a train along a straight

horizontal track from the moment when it passes a point A on the track.

Use the figure to plot a velocity-time graph of the journey shown in the figure below clearly showing your work.

18. a) Hot milk in a bottle cool faster when wrapped in a wet cloth than when the bottle is immersed in cold water

in a bucket. Explain. (2marks)

b) In an experiment to determine the specific heat capacity of liquids, a student used 2.0kg of each of the

liquids water, glycerin and paraffin. Each of the liquids was supplied with 21600J of heat energy under the

same conditions. The table below shows the temperature rise for the liquids.

Liquid Water Glycerin Paraffin

Temperature 2.6 4.4 4.9

c) In an experiment to study cooling, naphthalene was placed in a test tube and melted in boiling water. A

thermometer was then placed into the tube and reading of temperature taken at various time as it cooled.

The graph below represent the cooling curve of naphthalene.

Explain the shape of the curve between the following points: XY, YZ, ZA (3marks)

Time (minutes)

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 Temperature

400

360

320

280

240

200

160

120

80

40

PV

(joules)



232 / 2

PHYSICS

Paper 2

(Theory)

July / August, 2013

SECTION 1: (25 Marks)

1. A suspended plane mirror makes an angle of 300 with a wall. Light from a window strikes the mirror horizontally.

Find:

i) The angle of incidence (1 mark)

ii) The angle formed between the mirror and the reflected ray. (2 marks)

2. A charged body is gradually brought towards a pear- shaped conductor mounted on an insulating stand until it touches it as

shown in figure 1 below.

Which type of charge resides on the sphere? Explain. (2 marks)

3. When a lead-acid accumulator is left in a discharged condition for a long time, its plates suffer from sulphation.

What is meant by the term sulphation? (1 mark)

4. State any two conditions that must be met when magnetizing a steel metal rod by hammering. (2 marks)

5. Explain how concave mirror can be used by a dentist to examine a tooth. (2 marks)

6. When a hole of pinhole camera is made larger, the image undergoes certain changes. State any two changes on the image

formed. (2 marks)

7. A convex mirror of focal length 9cm produces an image on its axis 6cm from the mirror. Determine the distance

separating the object from the image. (3 marks)

8. Define focal plane with respect to optical thin lenses. (1 mark)

9. State the purpose of carbon powder dipped in ammonium chloride paste in a dry cell. (2 marks)

10. A light aluminum plate loaded with a mass m is suspended between the poles of a magnet from a spring as shown in

figure 2 below.

When mass m, is pulled down gently and released, current flow in the aluminum plate. Explain. (1 mark)

11. Sketch the frequency- wavelength graph of a wave travelling from one point to another. (1 mark)

12. A cogged wheel rotating uniformly produces sound of wavelength 1.65m. It makes 600 revolutions per minute. Find the number

of teeth on the wheel given that velocity in air is 330m/s. (3 marks)

13. Plot the magnetic field pattern of a conductor carrying current represented by the dot (.) and cross (x) in figure 3 below.

SECTION II: (55Marks)

14. a) What is an oscillation? (1 mark)

b) Explain how humidity affects the speed of sound in air. (2 marks)

c) Figure 4 below shows a wave of water (ripple)

i) What is the amplitude of the wave? (1 mark)

ii) If speed of the ripple is 30cms-1 and distance AB is 3cm, find the period T, of the water ripple. (3 marks)

d) Straight plane waves in a ripple tank are incident at an angle to the shallow end of the tank as shown in figure 5 below.

On the same diagram, draw the rays after completely entering the shallow end of the ripple tank. (2 marks)

15. a) Define threshold frequency. (1 mark)

b) Sodium vapour lamp of power 60 W emits light of wavelength 5.82 x 10-7m. Calculate the number of photons emitted by the

lamp in each second. (Take plank’s constant, h = 6.63 x 10-34Js), speed of light (3.0 x 108m/s) (3 marks)

c) The graph below shows variation of frequency, f of incident radiation with kinetic energy of emitted electrons.

From the graph, determine,

i) Plank’s constant, h (4 marks)

ii) Hence calculate the work function of the metal. (3 marks)

16. a) What is an extrinsic semi-conductor? (1 mark)

b) State three changes that take place when a p-n junction semi-conductor is reverse biased. (3 marks)

c) i) Sketch a circuit diagram used to achieve half-wave rectification from an a.c signal. (3 marks)

ii) Explain how the circuit drawn above helps in achieving half-wave rectification. (2 marks)

iii) Sketch the graph of the rectified signal. (1 mark)

d) State two advantages of using a bridge rectifier circuit over a single diode rectifier. (2 marks)

k.e (J)

Frequency of

(x 10-34) Hz

17. Figure 6 below shows a Geiger-Muller tube (GM tube)

a) Name the parts labelled X and Y (2 marks)

b) Which gas is found inside the cylindrical tube? (1 mark)

c) How are avalanche electrons produced? (2 marks)

d) What is meant by dead time? (1 mark)

e) What is the purpose of the gas in the G.M tube? (1 mark)

f) For a certain radioactive material, the average count rate is found to be 96 counts per second. After 200 seconds, the count rate

dropped to 28.5 counts per second. If the background count rate was 24 counts per second, find the half-life of the material.

(3 marks)

18. a) Complete the ray diagram below to show the position of the object. (3 marks)

b) State two causes of hypermetropia. (2 marks)

c) A defective eye focuses a distant object as shown in figure 7 below.

i) State the defect. (1 mark)

ii) Suggest a suitable lens to correct the defect. (1 mark)

d) An eye has a far point of 5.0m and a normal near point. Determine the focal length of the lens used to correct his defect.

(3 marks)

e) Sketch a diagram showing how a simple microscope magnifies an object. (3 marks)



232 / 3

PHYSICS

Paper 3

(Practical)

PART 1

1. You are provided with the following apparatus.

- A piece of thread 1.4m long

- A complete stand.

- 2 pieces of timber (to hold the thread in the clamp)

- A stop watch (clock)

- A pendulum bob.

- A metre rule

Procedure

1. Tie the thread on the bob to make a pendulum

2. Fix the pendulum on the stand as shown in the figure below.

3. Make L equal to 0.3m.

4. Displace the bob slightly to one side about ½cm from rest position and allow it to swing to and fro.

5. Measure and record the time for 20 oscillations in the table below.

6. Repeat steps 3, 4 and 5 for the other values of L in the table.

a) Complete the table below. (4marks)

Length L (cm) Time t(s) for 20(oscillations) Periodic Time (T(s) T2 (s2)

0.3

0.5

0.7

0.9

1.0

1.2

b) i) Plot the graph of 1 (m) against T2 (s2) (4mks)

ii) Find the gradient S, of the graph. (2mks)

iii) Given that M = 4𝜋2𝑆, find the value of M. (1mk)

iv) State the significance of M. (1mk)

PART II

You are provided with the following apparatus

- Two identical 100g masses.

- Uniform metre rule (wooden)

- Liquid – water

- Complete retort stand

- Varnier calliper

- Three (3) pieces of thread

Procedure:

i) Take one 100g mass, measure its diameter, d and height, h using the vernier calliper provided.

d = __________________ cm h = __________________ cm

ii) Determine the volume v, of the mass, given.

V = 𝜋 (𝑑

2)

2 x h V = ______________

iii) Using the formula = 𝑚

𝑣 determine the density of the solid. =

100

𝑉 = ________________ (1mk)

iv) Using the retort stand and the thread, adjust the metre rule so that it balances at its centre of gravity(c.o.g). This

position should be maintained throughout the experiment.

v) With the distance for the mass in liquid at 30cm from c.o.g, adjust the position of the other mass to obtain

balance condition shown in the figure below

Record the corresponding distance y. y = _____________________________________cm (1mk)

vi) Using the principle of moment determine the apparent weight. (lmk)

vii) Given upthrust = wt, in air - Apparent weight determine upthrust U. (lmk)

viii) Determine the relative density of one of the solid masses provided. (2mks)

2. PART I_

You are provided with:

- One triangular glass prism.

- four optical pins

- two or four thumb pins.

- One soft board.

- One ½m or 1m rule

- some plastacine

- two sheets of white plane paper.

a) Measure one of the angles GAC of the prism and mark it with plasticine; Angle GAC = XO = (lmk)

b) Draw the outline of the prism on the white sheet of paper. Draw a line BO so that angle BON = 300 =i and OA is

about one- third of AG. Place the paper on the soft board and secure it with thumb pins. Erect pins P and Q

vertically on BO. Replace the prism on its outline and view pins P and Q through side AC and place pins S and T

in line with the images of P and Q. See figure 1

Extend ST to meet side AC at K. Produce (extend) lines BO and TK to meet at L and measure the angle of

deviation D= angle JLT. Record in table 1. Repeat for other values of 1 given in table 1 below.

D0 30 35 40 45 50 55 60

i0

c) Draw the graph D0 against i0. (3mks)

d) From the graph determine minimum value Dn of D. Dn = ____________________ (1mk)

e) Determine Z given; Z sin (𝑋0

2) = sin (

𝐷𝑚0+ 𝑋0

2) (3mks)

Part 2

You are provided with the fo11owing

- A voltmeter .

- An ammeter

- A switch labelled s

- A resistor R.

- Six connecting wires at least four with crocodile

clips at one end

Proceed as follows:

a) Set up the circuit as shown in the, figure below.

b) With the switch S, open, record the reading E of the voltmeter.

E = _________________________volts (lmk)

c) Close the switch (S). Record the current I flowing in the circuit and the potential difference V, across the cells.

I = __________________________A

V = ________________________volts

d) i) Complete the value 𝐸

𝐼 (1mk)

ii) Determine the value of K given that E == (10 + k)

iii) State the significance of K. (lmk)

MERU COUNTY FORM 4 JOINT EVALUATION, 2013


232 /1

PHYSICS

Paper 1

(Theory)

July / August 2013

1. Figure 1 shows a measuring cylinder which contains water initially at level A. A solid of mass 14g is immersed

in the water. The level rises to B. Determine the density of the solid to 2.d.p. (2mks)

2. Name two forces that determine the shape of liquid droplet on a solid surface. (2mks)

3. State two properties of a liquid that can be used as a brake fluid. (2mks)

4. A bottle of perfume is opened in one corner of a room in which the windows and doors are closed to stop

drought. The scent slowly spreads to all parts of the room. Explain why the scent spreads slowly even though the

molecules are moving fast. (1mark)

5. Figure 2 shows an inverted round bottomed flask with a capillary tube immersed in water.

State what happens when the temperature of the flask was lowered below the initial temperature. (1mark)

6. In figure 3 below, one end of a metal rod is placed in steam and the other end in melting ice. The length of the

rod in between is lagged.

State two factors that determine the rate at which ice melts. (2mks)

7. A student used vernier calipers to measure the diameter of the test tube. He read it to be 1.76cm. Determine the

actual diameter of the test tube if the vernier calipers had a negative error of 0.09. (1mk)

8. Figure 4 below shows a uniform half meter which is balanced by a weight of 30N at one end. If the pivot is

placed 8cm from the same end, calculate the weight of the rod. (3mks)

9. A spring has a spring constant of 4N/M. Three such identical springs are arranged as shown in figure 5 below.

Determine the weight of mass m if the extension produced is 37.5mm. (2mks)

10. Figure 6 below shows a horizontal glass tube PQ with tubes X, Y and Z fitted to it. Water is allowed to flow

through it steadily from P to Q without turbulence. (1mark)

i) Compare the velocity of water at O and R. (1mark)

ii) What is the relationship between pressure of water and its velocity at any point along the tube PQ? (1mark)

11. A ball is thrown vertically upwards from the ground. It rises up to the highest point and then returns to the

ground. On the axis provided below sketch the velocity time – graph for the motion. (2mks)

12. State Newton’s second law of motion. (1mk)

13. Figure 7 below shows a car of mass M moving along a curved part of a road with constant speed.

Explain why the car is more likely to skid at B than A, if the same speed is maintained. (2mks)

14. Figure 8 below shows a cork floating in water and held to the bottom of the beaker by a thin thread.

Name two forces acting on the cork. (2mks)


15. a) i) A bullet is fired from a gun at a velocity of 15ms-1. It strikes a tree perpendicularly and penetrates deep.

If it stops as it emerge through the other side of the tree. Calculate the average retardation, if the tree is

1.8m thick. (3mks)

ii) Calculate the time taken for the bullet to emerge. (3mks)

b) i) Define momentum of a body. (1mk)

ii) A lorry 20 tonnes travelling at 20 ms-1 collides with a pickup of mass 3 tonnes travelling 30 ms-1 in the

opposite direction. The two stick together and move in one direction calculate the speed of the two

vehicle after the collision. (3mks)

iii) A footballer kicks a ball of mass 0.6kg initially at rest using a force of 720N. If the foot was in contact

with the ball for 0.1 seconds what was the take-off speed of the ball? (2mks)

16. a) Differentiate between work and energy. (1mk)

b) The figure below shows a section of an internal combustion engine.

i) What kind of energy is available at point A? (1mk)

ii) Name any other two forms of energy that are outcomes of the explosion. (2mks)

c) Figure 9 below shows how the potential energy of a body projected vertically upwards varies with time.

On the same axes sketch the graph to show how kinetic energy of the body varies with time. (1mk)

d) A man uses the inclined plane shown in figure 10 below to lift a load of mass 100kg through a vertical

distance of 8m. The inclined plane has an efficiency of 80%.

i) Calculate the velocity ratio of the machine. (2mks)

ii) Calculate the effort needed to move the load up the inclined plane. (3mks)

iii) Calculate the work done against friction in raising the load through 8m. (3mks)

17. a) Define the term specific heat capacity. (1mk)

b) You are provided with a well lagged colorimeter half filled with water of known mass, a stirrer, a piece of

metal, a thermometer, some water in a beaker, a balance and a source heat.

i) Describe an experiment that can be used to determine the specific heat capacity of the metal. Assume that

the calorimeter has negligible heat capacity. (2mks)

ii) State the measurement required in the experiment and show how they would be used to obtain C. (4mks)

c) 100g of a solid x was heated in a container by an electric heater rated 50w for some time. The graph below

shows the variation of the temperature of the solid with time.

i) Determine the quantity of heat supplied by the heater from the time the solid starts to melt to the time it has

all melted. (2mks)

ii) Determine the specific latent heat of fusion of solid x assuming the container absorbs negligible amount of

heat. (2mks)

18. a) i) Figure 11 below shows two masses 0.1 kg and 0.2 kg connected by a string through a hole on a

smooth horizontal surface.

The 0.1 kg mass rotates in an horizontal circle of radius 3cm. Calculate the angular velocity when the

system is at equilibrium. (3mks)

ii) A glass block of mass 100g is placed on a turntable which is rotating at a constant angular velocity of

7.07 rads-1. If the friction between the glass block and the turntable is 0.4N determine the force

required to hold the glass block at a distance of 12cm from the centre of the table. (2mks)

iii) State with a reason whether or not a 200g glass block placed at 8cm from the centre will slide. (1mk)

b) Figure 12 and 13 below show the scale reading before and after an object was completely immersed in

a liquid.

Find the density of

i) The solid (2mks)

ii) The liquid

iii) The reading on the compression balance when the object is fully immersed. (2mks)

19. Figure 14 below shows an apparatus that a student used to investigate the relationship between the temperature

and pressure of a fixed mass of gas at a constant volume.

a) Explain how the student should ensure that all the air trapped has the same temperature as that indicated by the

thermometer. (2mks)

b) Explain why it is necessary to ensure that before taking any reading on pressure mercury level should be at the

level marked y. (1mk)

c) State the law the student is investigating. (1mk)

d) If x and y were at the same level at a temperature of 270c, determine the final temperature when y is at a height

32 and x at a height 70cm mark as shown. Take atmospheric pressure = 76cmHg. (3mks)

MERU COUNTY FORM 4 JOINT EVALUATION - 2013


232 /2

PHYSICS

Paper 2

(Theory)

July / August 2013

1. Figure 1 below represents a point image formed by a plane mirror.

Sketch rays to show how the image is formed. (2mks)

2. A polystyrenes ball coated with aluminium is freely suspended between two highly charged rods as shown in

figure 2 below.

The ball is found to swing between the two rods as it touches one of them at a time. Explain the cause of this

behavior of the ball between the rods. (1mk)

3. Distinguish between polarization and local action as defects of a simple cell. (1mk)

4. State one property of images formed by plane mirrors. (1mk)

5. A sketch carrying wire is placed between the poles of a magnet as shown in figure 3 below.

Sketch the magnetic field pattern between the poles. (1mk)

6. Figure 4 below shows a wave form. Determine the period of the wave. (1mk)

7. A student stands between a high wall and a thick forest. After clapping her hands, he receives an echo from the

wall after 0.1 seconds and after another 0.5 seconds; he receives another echo from the thick forest. Given that

the speed of sound in air is 330 ms-1, determine the distance between the wall and the forest. (3mks)

8. Explain why a radio aerial dish uses a parabolic metal reflector as opposed to a spherical one. (1mk)

9. A torch bulb is labeled 2.5V, 0.3A. Calculate the power of the bulb. (2mks)

10. Two dry cells in series provide an e.m.f. of 3.1V. When a load of 6.9 is connected in series, the current drawn is

0.33A. Calculate the internal resistance of the cell. (3mks)

11. An upright object was placed in front of a converging lens. An image magnified three times was formed on the

screen. I f the distance between the object and the screen was 80cm, determine, the object distance. (3mks)

12. Figure 5 below shows the electromagnetic spectrum.

Gamma rays A Ultraviolet

radiation

Visible light Infrared

radiation

Radio waves

a) Identify A. (1mk)

b) State one use of A. (1mk)

13. Explain why long distance power transmission is done at a very high voltages. (1mk)

14. The accelerating potential in a x-ray tube is 50KV. Determine the kinetic energy of an electron (Electronic

charge, e = 1.6 x 10-19c) (3mks)


15. a) A bar magnet is suspended from a spring balance attached to a fixed support in figure 6 below and hangs

over a coil.

i) Indicate on the coil the direction of current when the switch is closed. (1mk)

ii) State and explain what happens to the spring balance when the switch is closed. (2mks)

iii) What would be observed on the spring balance if the current is increased? (1mk)

iv) Other than increasing current, how else can the observation in (iii) above be achieved? (1mk)

b) i) Define mutual induction. (1mk)

ii) State two factors that determine the magnitude of e.m.f induced in a coil. (2mks)

iii) Figure 7 below shows an induction coil used to produce sparks.

(I) Name the parts labeled A, B and C. (3mks)

(II) Explain the purpose of part A. (1mk)

16. a) i) Figure 8 below shows two negatively charged metal plates. Complete the diagram to show the electric

field between the plates.

ii) Fig 9 below shows a resistor – capacitor circuit that can be used to charge a capacitor C.

(I) When the switch is closed, the charging current is initial high but gradually falls to zero. Explain this

observation. (2mks)

(II) On the axes provided in figure 10 below, sketch the graph of potential differences across the capacitor plates

against time. (1mk)

iii) Three capacitors are arranged as shown in figure 11 below

Given that the charge on capacitor C in 20 MC, determine the potential difference V, shown in the diagram.

(3mks)

b) Figure 12 below represents resistors arranged in a circuit.

i) Calculate the effective resistance R, between points X and Y. (2mks)

ii) Determine the voltage, B across points X and Y. (2mks)

iii) Find the value of current I2. (1mk)

17. a) The diagram in figure 13 below shows part of a cathode ray tube.

A

C

B

Soft iron

Springy rods

Contact

Time (seconds)

p.d across capacitor

plates (V)

i) Explain how the cathode rays are produced. (2mks)

ii) On the same diagram, draw the path of the cathode rays to the spot produced on the screen at D. (1mk)

iii) Explain the observation made on the spot when the connection to the high voltage supply are interchanged

so that the anode is made negative. (2mks)

iv) State one property of cathode rays. (1mk)

b) A certain surface of a metal is illuminated with light of different frequencies and the corresponding stopping

potentials measured. The graph in figure 14 below shows how frequency f varies with stopping potential, Vs

for the metal.

Given that eVs = hf = hf0 and that e = 1.6 x 10-19c, determine from the graph;

i) h (3mks)

ii) f0 (2mks)

18. a) i) Figure 15 below shows a ray of monochromatic light p incident on a perplex prism.

Complete the figure by drawing a ray diagram showing the path of the light as it traverses through the

prism and into the air.

ii) Determine the refractive index of diamond given that its critical is 240c. (3mks)

iii) State two conditions necessary for total internal reflection to light to occur. (2mks)

b) i) (I) Define diffraction. (1mk)

(II) Figure 16 below shows wave fronts approaching an object. On the same diagram, draw the wave form

after it passes the object. (1mk)

ii) State two conditions necessary for the formation of a stationary wave. (2mks)

19. a) i) Explain the effect of increasing temperature on the conductivity of a metal conductor. (2mks)

ii) Figure 17 below shows a circuit comprising a dry cell, two diodes, ammeter and three resistors.

Determine the ammeter reading given that the cell has an e.m.f of 2.0V. (2mks)

b) i) The following is a nuclear reaction which results in emission of some particles.

(I) Identify the particles x and y. (2mks)

(II) How many particles of x are involved in the reaction? (1mk)

ii) (I) Define half – life of a radio-active material. (1mk)

(II) The half-life of a radioactive substance is 118 days. A sample of the substance has 4 x 1010

un-decayed nuclei at time t = 0. How many un-decayed nuclei will be left after 472days?(3mks)

MERU COUNTY FORM 4 JOINT EVALUATION, 2013


232 /3

PHYSICS

Paper 3

(Practical)

July / August, 2013

QUESTION 1

1. You are provided with the following:

- A metre rule.

- A retort stand, a boss and clamp.

- Three pieces of thread.

- 200ml of water in a 250ml beaker labeled W;

- 200ml of a liquid in 250ml beaker labeled L;

- Two masses labeled M1 and M2.

Proceed as follows;

a) Suspend the metre rule so that it balances as its centre of gravity G and hang the masses as shown in figure 1

G = ………………cm (1mk)

b) Position mass M at a distance x = 5cm from the centre of gravity G and adjust the position of M1 so that the

Meter rule balance at G. Record the X1 of M1 from the point G in table 1.

c) While maintaining the distance x = 5cm, immerse M2 completely in water. Adjust the position of M1 until the

meter rule balances again (see figure 1 (b). Record the new distance x2 .

d) Still maintaining the same distance x = 5cm, remove the beaker W with water and replace it with the beaker L

with the liquid. Immerse M2 completely in the liquid. Adjust the position of M1 until the meter rule balances again

(see figure 1 (c). Record the new distance x3 .

e) Remove mass M2 from the liquid and dry it with a tissue paper.

f) With the meter rule suspended from its centre of gravity G, repeat the procedure in (b),(c),(d) and (e) for other

values of x given in table 1. Compare the table

Table 1

Distance x (cm) Distance x1 (cm) Distance x2 (cm) Distance x3 (cm) L =(x1 - x1 ) (cm) L = x1 – x3 (cm)

5

10

15

17

20

23

g) Plot a graph of L0 (y-axis) against L1 (5mks)

h) Find the slope of the graph. (3mks)

i) Find the value of K given that L1 = 25

𝑘 Io (2mks)

QUESTION 2

PART 1

You are provided with the following:

- A voltmeter

- 2 dry cells and a cell holder.

- A switch

- A resistor labeled R 10

- A wire mounted on a non-scale and labeled G.

- A micrometer screw gauge (to be shared).

- Six connecting wires with six crocodile clips.

- Jockey

Proceed as follows; a) Record the length L0 of the wire labeled G.

L0 =………………………

Use the micrometer screw gauge provided to measure the diameter of the wire labeled G at two different points and

determine the average diameter, d.

The diameter d1 = …………..mm, and d2 = …………….mm (1mk)

Average diameter d = …………..mm. (1mk)

Determine the radius r of the wire in metres.

Radius r = …………m. (1mk)

b) Connect the voltmeter across R as shown in figure 2 below.

Adjust the position of one crocodile clip on the wire G to a point such that the length 1 of the wire in the circuit

Is 5cm. (see figure 2) close the switch.

c) Repeat the procedure in (c) above for the other values of L shown in table 2.

Distance l (cm) 0 5 10 20 30 40 60 70

p.d across R, V (v)

Table 2

d) (i) On the grid provided plot the graph of V (y-axis) against L. (5mks)

ii) From the graph, determine L1 the value of L when V = 3𝑉

4 where V0 is the p.d where L = 0 (1mk)

e) Determine the constant D for the wire given that

D = 𝑅

11 x

25

𝑉0 (2mks)

f) Determine the constant 𝑝 given that

𝑝 = 𝜋r2D, where r is the radius of the wire in metres. (2mks)

PART II


- Lens.

- White screen

- Candle

- Metre rule

Proceed as follows: a) Set up the apparatus such that the distance, L between the lit candle and the screen is 50cm as shown in the figure

below.

b) Place the lens such that an enlarged image of the candle is formed on the screen. Record the distance from the

Lens to screed d1 …………. (1mk)

c) Without altering the distance , L move the lens to a position so that a diminished sharp image is formed on

the screen. Record the new distance of the lens from the screen d2 ………………. (1mk)

d) i) Determine the value of d from d = d1 - d2 ……………. ( ½ mk)

ii) Given that K = 𝐿2= 𝑑2

4𝐿 determine k. (1½mk)

GEM DISTRICT FORM 4 JOINT EVALUATION TEST, 2013


232 /1

PHYSICS

Paper 1

July / August, 2013

SECTION A (25 MARKS)


1. Determine the reading of the vernier calipers shown in figure 1 below. (2mks)

2. Figure 2 below shows two forces F1 and F2 acting on a uniform rod. The system is at equilibrium.

If the reaction force at the pivot is 36N. Determine the magnitude of F1 and F2 (2mks)

3. Figure 3 shows two capillary tubes of different cross sectional areas dipped in a trough of mercury. The level of

mercury in tube A is marked on the figure. Mar on the same figure the level of mercury in tube B. (1mk)

4. Figure 4 below shows a bimetallic thermometer.

Explain how the thermometer works. (2mks)

5. Figure 5 below shows a heater placed between two similar metal cans C1 and C2 filled with kerosene and

Thermometer T1 and T2 immersed in the liquids. The outer surface of C1 is shiny while that of C2 is dull black.

Explain one adjustment which can be made to C2 so that it takes same time interval for the readings of T1 and T2

to be the same. (2mks)

6. An object of mass 30g is dropped from a height of 20m and attains a velocity of Vm/s just before hitting the

ground. Determine the change in momentum upon hitting the ground. (3mks)

7. Figure 6 below shows water in a measuring cylinder.

Mark on the diagram the level x of water in the cylinder when a stone of mass 60g and density 12000kg/m3 is

completely immersed in water inside the cylinder. (2mks)

8. Figure 7 below shows an incompressible, non-viscous fluid flowing across a tube of varying cross sectional

areas. P1 P2 P3 and P4 represent the pressure of the fluid at different sections of the tube of flow.

Write down the magnitudes of P1 P2 P3 and P4 in order of increasing magnitude to the right. (1mk)

9. A body of mass 0.1kg weighs 0.88N in liquid X. Determine the relative density of liquid X. (3mks)

10. An immersion heater rated 3KW is used to heat 800g of a liquid from room temperature. Figure 8 below shows

a graph of temperature against time as the liquid gets heated up to boiling point.

Use the graph to determine specific heat capacity of the liquid. (3mks)

11. Give a reason why water is not preferred for as a barometric liquid. (1mk)

12. A body of mass 1kg is attached to the end of an inextensible rope and whirled in horizontal circle with a velocity

of 9m/s. If the tension on the rope is 72N, determine the length of the rope. (2mks)

13 a) i) Give any two ways of increasing the capacitance of a parallel plate capacitor. (2mks)

ii) Figure 8 below shows a capacitor network.

Calculate the charge on the 1.5µF capacitor in figure 8 above. (3mks)

b) A student used the set up below, (figure 9) to investigate how voltage V varies with current, I for a variable

resistor.

On closing the switch, the following results were obtained for different values of V and I.

V (volts) 2.65 2.58 2.00 1.83 1.00 0.25

I (Amperes) 0.10 0.21 0.50 0.65 1.20 1.70

i) Using the data above, plot a graph of V (y- axis) against I (x- axis). (5mks)

ii) Given that the equation E = V + Ir holds for the experiment, determine the value of r. (2mks)

14. a) i) State two properties common to all electromagnetic waves. (2mks)

ii) The table below gives types of radiation, their detectors and uses.

Types or radiation Detector Uses

Radio waves

Phototransistor of blackened thermometer Warmth sensor

Fill in the blanks above appropriately. (2mks)

b) In the Young’s slit experiment, an interference pattern of bright and dark fringes was formed as shown in

figure 10 below by monochromatic light of wavelength λ coming from a source through slits M and N.

i) Write an expression for the path difference between MX and NX where X corresponds to the 2nd bright

fringe. (1mk)

ii) Explain how the dark and bright fringes are formed. (2mks)

iii) State and explain what would happen on the screen if the slits M and N were made larger. (2mks)

c) In Young’s double slit experiment, mercury green light of wavelength 5.4 x 10 -7 m was used with a pair of

parallel slits of separation of 0.60mm. The fringes were observed at a distance of 40.0cm from the slits.

Determine the fringe separation. (3mks)

15. a) Distinguish between thermionic emission and photo - electric effect. (1mk)

iii) The tension on the string, take g = 10N/kg and density of air = 1.25 km/m3 . (2mks)

c) A uniform cylindrical metal rod of diameter 14cm and length 0.8m rests on a flat surface with the circular

force in contact with the surface. The density of the rod is 3.6g/cm3. Determine:-

i) The weight of the rod. (2mks)

ii) The pressure exerted by the rod on the surface. (2mks)

16. a) Using kinetic theory of gases, explain how a rise in temperature of a gas causes a rise in pressure of the gas

at constant volume. (2mks)

b) The set up in figure 17 below may be used to verify one of the gas laws.

i) State two functions of concentrated sulphuric acid. (2mks)

ii) Describe how the apparatus in figure 13 above can be used to verify the law under investigation. (5mks)

17. a) A stone is thrown vertically upwards from a pit latrine under construction. The stone goes beyond the edge

of the latrine and eventually falls back to the edge of the latrine without bouncing. Taking upward velocity

to be positive, sketch in figure 15, a velocity- time graph for the motion of the stone. (2mks)

b) A driver of a car moving at 20 ms-1 notices a road block in front of him. He takes o.2 seconds before applying

brakes and then takes 2 seconds before bringing the car to rest. Determine;

i) The average deceleration of the car. (2mks)

ii) The distance between the car and the roadblock when the car comes to rest. (3mks)

c) The ticker tape in figure 16 below was made by a ticker timer whose frequency was 50HZ.

Determine the acceleration of the motion. (4mks)

18. a) State one similarity between moment of force about a point and work. (1mk)

b) Man pulls a body of mass 20kg up an inclined plane using a force of 48N. The body moves along the incline

a distance of 100m in 40 seconds.

Figure 17(b) below shows a graph of vertical height through which the machine raises the body with time.

i) Determine the power output of the machine after 40 seconds. (2mks)

ii) The efficiency of the machine. (3mks)



232 /2

PHYSICS

Paper 2

SECTION A: (25 MARKS)

1. A white paper is a good reflector of light but does not form an image like mirror. Explain this observation.

(2mks)

2. The set up in figure 1 below can be used in a laboratory for lifting and releasing a steel ball.

i) Which material is suitable for use in the core? (1mk)

ii) If a slight larger ball is to be lifted, it is necessary to make an electromagnet stronger. State two ways of

increasing the strength of the magnet. (2mks)

3. Figure 2 below shows the behavior of light rays from a distant object falling on the eye.

i) State the defect shown above. (1mk)

ii) On the figure, show how the defect above in part (i) can be corrected. (2mks)

4. The two conducting balls shown in figure 3 below are identical and contain the number of excess electrons

indicated. The two balls are made to touch. How much charge in coulombs, will each have? (e = 1.6 x 10-19C)

5. The count rate of a radioactive indium falls from 3200 counts per minute to 200 counts per minutes 220minutes.

Determine the half – life of the radioactive isotope. (3mks)

6. Figure 4 below shows the profile of transverse wave.

Identify two sets of points other than b and g that are a wavelength apart.

7. State the reasons why sound of thunder is always heard sometime after the lightening flash is observed. (1mk)

8. The diagram below, figure 5 shows a coin placed at the bottom of a tank so that it is beyond the view of the eye.

Sketch the rays to show how the coin can be brought into view when water is added into the tank to a suitable

level.

9. Figure 6 below shows a ray of light being incident on a mirror.

Eye

Determine the angle of reflection? (1mk)

10. The voltmeter in figure 7 (a) and the ammeter in figure 7 (b) below read 2.1v and 0.35a respectively

Determine the reading in the voltmeter and ammeter in fig 7(c) and 7(d) respectively. (The lamps are identical

(2mks)

11. Give any two causes of energy loss in a transformer. (2mks)

12. State directional property of a magnet. (1mk)



13. a) The temperature of water in a measuring cylinder is lowered from 00C to 200C. Figure 9 shows a graph of

volume of water against thermodynamic temperature.

Determine the value of temperature T. (1mk)

b) State two factors that affect melting point of water. (2mks)

c) When a Bunsen burner is lit below wire gauze, the flame initially burns below the wire gauze (see figure

10(i). After some time, the flame penetrates and burns above the wire gauze as well in figure 10(ii) Explain

the observations. (2mks)

13. a) Figure 11 below shows features of a vacuum flask.

i) Name the parts labeled A and B. (2mks)

ii) Explain how the part labeled A is useful in the function of the flask when carrying a hot liquid. (2mks)

14. a) Three identical spring balance Q, R and S each weighing 1.0N are arranged as shown in figure 12 below.

Determine the reading on

i) Spring Q. (2mks)

ii) Spring R. (1mk)

b) You are provided with the following apparatus.

- A wire

- A test tube

- An assortment of masses

- A complete stand, clamp and boss.

Using the above apparatus only, describe an

experiment to verify Hooke’s law for a spring using

the following steps.

I) Making a spring. (1mk)

II) Assembling the apparatus. (2mks)

III) Recording and analysis of data. (4mks)

15. a) Explain why a steel ship floats on water yet steel is denser than water. (1mk)

b) A balloon whose volume is 1.6 m3 is tied by a rigid support and is filled with a gas of density 0.2kg/ m3 as

shown in the diagram in figure 13 below. The fabric of the balloon is 0.4kg.

Determine;

i) The weight of the balloon fabric. (1mk)

ii) The upthrust force experienced by the balloon. (2mks)

b) Draw a well labeled diagram of an experimental set up for observing photo – electric effect. (3mks)

c) The table below shows the relationship between the wavelength λ, of a radiation falling on a surface and the

energy of E of the emitted electrons. Take speed of light to be 3 x 108m/s.

λ (m) x 10-7 2.0 1.5 1.0 0.5

E (J) x 10-19 10 13 20 40

Frequency (f) x 1015(Hz)

i) Plot a graph of energy E against the frequency f of the incident light. (7mks)

ii) Determine the work function, WO of the surface used. (Take C = 3.00 x 108m/s & h6.663 x 10-34Js) (3mks)

iii) State one disadvantage of half- wave rectification using a junction diode. (1mk)

16. a) State Lenz’s law of electromagnetic induction. (1mk)

b) Determine the direction of the current in the coil in the set up in figure 12 below. Label the polarity at the

points marked X and Y.

d) In a radio therapy unit of a hospital, a transformer is used to supply a potential difference of 150 KV to an

X-ray tube from a 240V a.c. main supply. A current of 100m A flows in the X- ray. Assuming the

transformer is 100% efficient, Determine

i) the current in the primary coil (2mks)

ii) The ratio of number of turns of the secondary to the number of turns of the primary. (2mks)

17. Figure 13 below shows the main components of a cathode ray tube. Use it to answer the questions that follow.

i) Name the parts labeled P, R and M. (3mks)

ii) Explain how the electrons are produced in the tube. (2mks)

iii) State and explain the function of the grid. (2mks)

iv) State and explain what would be observed on the screen if an a.c voltage is connected across the y-plate.

(1mk)

v) State how the deflection system of a coloured television differs from that of a C.R.O. (1mk)


232 /3

PHYSICS

Paper 3 (Practical)

Question one

Part one

You are provided with the following

- A voltmeter (0-5V)

- An ammeter (0-1A)

- 2 dry cells

- One torch bulb

- Resistance wire 6 1 M or longer

- 6 wires, 3 with crocodile clips

Proceed as follows:

a) Connect the circuit as shown in fig 1

b) Set the length, L at 10cm and record the ammeter and voltmeter readings.

c) Repeat the experiment with other values of L shown in the table.

L (cm) 10 20 30 40 50 60 70 80

I (A)

p.d (V)

d) On the axes provided below, plot a graph of current, I (y-axis) against the p.d. (5mks)

e) From the graph, determine the value of p.d across the bulb when the current it is 0.11A. (1mk)

f) Calculate the resistance R of the bulb when the current is 0.11 A (3mks)

Part two

You are provided with the following.

- A test tube

- A measuring cylinder (20 – 50 cm3) may be shared.

- One meter rule or half meter rule.

- A beam balance or electronic balance.

- A vernier caliper.

Proceed as follows:

a) Measure the depth L, of the test-tube using the meter

rule / half meter rule. L = ______cm. (1mk)

b) Using the vernier caliper, measure the external

diameter, d of the test tube.

d = ____________ cm. (1mk)

c) Determine the volume of the empty test tube using the

formula.

V1 = 𝜋𝑑2𝐿

4 V1 = ________________ (1mk)

d) Dry the test tube and measure its mass, M using an

electrical balance or beam balance

M = ________________ g. (1mk)

e) Fill the test tube completely with water (But the level

should not rise above the mouth if the test tube)

f) Transfer the water into a measuring cylinder and

record its volume, V2 . V2 = ___ cm. (1mk)

g) Obtain the volume, V of the glass material of the test

tube from the formula.

V= V1 – V2. V=____________ cm. (1mk)

h) Calculate the constant, K, of the material of the test

tube from

K = 𝑀

𝑉1− 𝑉2 K = ________gcm-3 (1mk)

Question two

You are provided with the following

- A meter rule

- A half –meter rule

- Retort stand, clamp and boss

- Two pieces of thread or string, about 40cm long.

Proceed as follows

a) Set up the apparatus as shown in fig 2 (a)

Ensure the loops on the meter rule ad half meter rule are loose to enable easy sliding of the threads along the rule.

Also the separation between the meter rule and the plank must be 20cm throughout the experiment.

b) Adjust the positions of the threads such that one is on the 5cm mark and the other on the 45cm mark on the

Half-meter rule i.e. d= 40cm. Maintain the threads vertical by making the separation of the loops on the meter

rule to be the same as on the half meter rule.

Displace one end of the half-metre rule slightly on a horizontal plane so that when released it oscillates about a

vertical axis as shown by the arrow in fig 2 (b). Measure the time taken for 20 oscillations and record the value in

table 2.

c) Repeat the procedure in (b) for others values of d shown in table 2. Complete the table. (9marks)

d (cm) d (m) 1

𝑑2 𝑚−2 Time for oscillations T(s) period T2(s2)

35

30

25

20

10

d) On the grid provided, plot the graph of T2 (y- axis) against 1

𝑑 (m-2) (5mks)

e) i) Determine the slope of the graph. (3marks)

ii) Given that T2 = 16

5𝑑2 𝐾2, where K is a constant, use the graph to determine the value of k. (3mks)

EMBU COUNTY FORM FOUR JOINT EVALUATION TEST, 2013


232/2

Physics

Paper 2

SECTION I

1. A ray of light is incident at an angle of 25° to a plane mirror. The mirror was rotated through an angle of 100.

Through what angle was the reflected ray rotated? (2mks)

2. Figure 1(a) and (b) shows two simple electric circuits, the bulbs are identical.

Fig 1(a) Fig 1(b)

When the switches, S are closed, which bulb will light more brightly? Give a reason for your answer.

3. Figure 2 shows a charged ball and an uncharged ball suspended freely close to each other.

State and explain what would be observed .

4. The set up in figure 3 shows a suspended magnet near a soft iron core in solenoid

State and explain the observation made when switch, S is closed .

5. Figure 4 shows the image I, formed by a concave mirror. Locate using rays the position of the object. (3mks)

6. Figure 5 shows a wire in a magnetic field. A current is switched on to flow to the wire in the direction indicated

On the diagram indicate the direction of motion of the wire. (lmk)

7. Figure 6 shows part of a displacement time graph of a wave travelling across water at a particular place with a

velocity of 0.2m/s

Determine the wavelength (3mks)

8. Suggest the reason for this observation. (2 marks)

9. State two factors that affect the heating effect of an electric current. (2mks)

10. Figure 8 shows with two bulbs and components D1 and D2

Soft iron core

S

Time, t(s)

Displacement

11. An electromagnetic wave is made to pass through an electric field.

i) State what is observed. (1mk)

ii) Explain your answer in (i) above. (1mk)

12. State two differences between cathode rays and x-rays. (2mks)

13. State one condition necessary for total internal reflection to occur. (lmk)

SECTION B (55 MARKS

Answer all the questions in the spaces provided

14. a) Figure 9 shows a magnet and a coil of a wire which is connected to a galvanometer.

When the whole magnet is moving slowly into the coil the needle of the galvanometer shows a steady

deflection to the right. Explain what happens to the galvanometer needle when the magnet is:-

i) Withdrawn slowly from the coil (lmk)

ii) Held steady inside the coil. (lmk)

iii) Moved quickly in and out of the coil. (lmk)

b) i) State one way in which power is lost in a transformer. (1mk)

ii) A transformer uses 240V a.c supply to deliver 9.0A at 80.0V to a heating coil. If 10% of the energy

taken from the supply is lost in the transformer itself, what is the current in the primary winding.

(3mks)

c) i) State one way of minimising power loss during transmission of electricity for long distances. (lmk)

ii) Find the cost of using 3KW immersion heater for a day if the cost per kWhr is 80cts. (3mks)

15. a) i) State one difference between stationary and progressive waves. (2mks)

ii) Figure 10 shows water waves incident on a barrier with a gap.

Complete the diagram to show the waves after passing through the barrier.

b) Figure 11 shows a monochromatic source of light placed infront of two narrow and close slits Sl and S2

i) How are the bright and dark fridges formed on the screen? (lmk)

ii) State the effect on the figure pattern if one slit is closed

c) i) State one factor that affect speed of sound in solids. (lmk)

ii) A man standing between two parallel vertical walls claps his hands. He hears the first echo 0.3 seconds

later and the next echo after a further 0.2 seconds. If the velocity of sound in air is 300m/s, calculate the

distance between the walls.

16. a) An Eskimo walking along an ice land observed an inverted image in the sky of a polax beat, standing some

distance away. Explain. (2mks)

b) The diagram in figure 12 shows a ray of light through a transparent material of refractive index 1.75.

Determine the value of angle S. (3mks)

c) i) The graph below shows the relationship between the image distance, V and the magnification, m for an

image formed by a convex lens.

If the equation of the graph is given by M = 𝑉

𝐹 C where C is a constant and F is the focal length of the lens.

Determine

i) The value of F (4mks)

ii) The value of C (1mk)

17. a) Distinguish between thermionic emission and photoelectric effect (1mk)

b) In an experiment to observe photoelectric emission from a clean caesium surface the result were used to plot

the following graph.

From the graph, determine;

i) The threshold frequency of the surface. (1mk)

ii) The Planck’s constant, h (charge of an electron e = 1.6 x 10-19c) (3 marks)

c) Figure 13 shows paths taken by three radiations A, B and C from a radioactive isotope through an electric

field.

i) State the charge on plate Y. (1mk)

ii) Identify the radiations A and C (2mks)

iii) Give a reason why C deviates less than A. (1mk)

Image distance V(cm)

18. a) i) Differentiate between potential difference (p.d) and electromotive force (e.m.f) (1mk)

ii) The e.m.f is greater than the p.d in a circuit. Explain. (1mk)

b) A student set up a circuit in figure 14 using three bulbs x, y and z each rated 65V, 1.0A

i) Determine the resistance of one of the bulbs when operated normally. (2mks)

ii) Calculate the effective resistance of the three bulbs. (2mks)

c) Figure 15 shows a battery of e.m.f 3.0V connected in series with two capacitos.

Determine the charge stored in the combined capacitors when the switch is closed. (3mks)

19. Figure 16 shows parts of a cathode ray oscilloscope (CRO)

Name the parts labelled A and B (2mks)

ii) What is the function of parts labelled C

iii) Explain how electrons are produced (1mk)

iv) Give a reason why the tube is evacuated. (1mk)

b) Figure 17 shows a bridge rectifier circuit

i) Insert the missing diodes, D2 and D4 (2mks)

ii) A capacitor has been connected across the resistor as shown above. On the axis provided draw the wave form

when a CRO is connected across resistor R. (1mk)

iii) If the capacitor was removed, sketch on the axis below the wave form as observed on a CRO. 91mk)

\

EMBU COUNTY FORM FOUR JOINT EVALUATION TEST, 2013


232/3

Physics

Paper 3

1. PART A:


Retort stand, boss and clamp.

A half metre rule

A 100cm3 measuring cylinder

A test tube

A beaker containing 110cm3 of coloured liquid

Another beaker containing about 20cm3 of water

Tongs

10cm3 measuring cylinder

Proceed as follows:-

a) Set up the apparatus as shown below.-

b) Put the coloured liquid in the measuring cylinder upto 100cm3 mark. Carefully slide the test tube into the coloured liquid

slowly using the tongs and not allowing any coloured liquid to enter the test tube. Note the height, Lo of the level of the

coloured liquid in the measuring cylinder using the half metre rule. Lo = ______________cm.

c) Using the 10cm3 measuring cylinder, measure 2.0cm3 of water and pour it into the test tube. Return the test tube in the

measuring cylinder. Record the new height L of the level of the coloured liquid in the measuring cylinder.

d) Repeat the procedure in (c) above for the values V = 3cm3 , 5cm3, 6cm3 and 8cm3 Record your values of L in the table

below and complete the table.

Volume V(cm 2 3 5 6 8

L(cm)

H = L - Lo (cm)

(4 mks)

e) i) On the grid provided, plot a graph of H(cm) against V(cm3) (5marks)

ii) Calculate the slope of the graph. (3mks)

iii) Given that S = 𝜋R2 where 𝜋 = 3.142 and s = slope, calculate the value of R. (2mks)

f) From the graph, determine the reading of the level of the coloured liquid in the measuring cylinder where 7cm3 of

water was put into the test tube. (lmk)

1. PART B

You are provided with the following apparatus.

A half - metre rule.

A knife edge.

A mass M.

A piece of thread

a) Place the half metre rule on knife edge and let it balance horizontally as shown below.

Record the balance point, C of the half metre rule. C = __________________cm

b) Using a string, hang the mass m at the 5cm mark and adjust the position of the knife edge until the half metre rule

balances horizontally again as shown below.

Measure and record the distance X (lmk)

X = ____________________________cm

c) Given that Y = C - (x + 5), Find y.

Y = ____________________________cm (lmk)

d) Given that P = 50𝑥

𝑦 find the value of p.

p = __________________________cm (lmk)

2. Part A

You are provided with the following:-

Two dry cells.

Nichrone wire mounted on a mm scale labelled AC SWG 28.

Ammeter 0 – 1.5A or 0 – 2.5A.

Cell holder.

Switch.

Voltmeter 0 - 3Y.

Eight connecting wires at least 4 with crocodile clips.

A jockey (can be substituted with a crocodile clip).

Proceed as follows:

a) Connect a circuit as shown in the diagram below .

b) i) With the switch open measure the e.m.f, E, of the cells. E = _____________V. (lmk)

ii) With AC equals to 70cm, close the switch and measure both the current and the pd across AC. Write the

results in the table below.

iii) Reduce the length AC as follows;

70cm, 60cm, 50cm, 40cm, 30cm. In each case record the current (I) and the corresponding pd (V). Enter the

results in the table below.

Length Ac (cm) 70 60 50 40 30 Current (I)

pd, V (Volts)

E-V (Volts)

Complete the table. (6mks)

c) i) Plot a graph of E -Von the Y-axis against I in (A) on X - axis

ii) Determine the gradient of the graph

iii) Given the equation E = V + Ir, determine internal resistance of the cell

PART 2 (B)


Converging lens with holders.

A screen with cross wires.

A metre rule.

A candle.

A match box (to be shared)

A white screen.

Proceed as follows:

d) Set up the apparatus as in fig below

e) Put the object (cross -wire) at a distance U = 40cm from the lens. Adjust the position of the screen until a sharp

image is formed on the screen. Record the distance V.

f) i) Repeat procedure (e) above for the distance U = 50cm and record the new distance V. Complete the table

below.

U(cm) V(cm) M= 𝑉

𝑈 M + 1

40

50

(3mks)

ii) Given F = 𝑉

𝑚+1, calculate the values off hence determine the average value Fav (2mks)

GUCHA SOUTH FORM FOUR EVALUATION TEST, 2013


PHYSICS

Paper 1

(Theory)

July / August, 2013

SECTION A (25 marks)

Answer all questions in this section in the spaces provided.

1. The figure below shows a measuring cylinder with water initially at level A. When a solid of mass 2.0g is fully

immersed in the water, the level rises to B.

Determine the density of the solid mass. (2 mark)

2. A body weighing l00N is found to weigh 80N when fully immersed in a certain fluid. Account for the

difference in the two weights. (1 mark)

3. State how the pressure of a fixed mass of gas can be increased at constant temperature. (l mark)

4. State two assumptions made when determining the diameter of an oil molecule in the oil drop experiment.

(2 marks)

5. Two identical springs are connected in series when a 50g mass is hang at the end of the springs, it produces an

extension of 2.5cm. Find the extension produced by the same mass when the springs are connected in parallel.

(3 marks)

6. A box of mass 500g is dragged along the level ground at a speed of l2ms-1. If the force of friction

between the box and the floor is 2000N, calculate the power developed. (3 marks)

7. State one common way in which heat losses by both conduction and convection are minimised in a thermos

flask. (l mark)

8. A bullet of mass 20g hit a tree trunk of diameter 60cm. If the velocity of the bullet decreases from 200m/ s to

l00m/s, determine the average retardation force which acts on the bullet. (3 marks)

9. Sketch a velocity-time graph of a body moving down a viscous fluid. (1 mark)

10. In a ball and ring experiment, the ball goes through the ring at room temperature. When it is heated it does not go

through the ring, but when left: on the ring for some time, it goes through. Explain this observation.

(2 marks)

11. A faulty mercury thermometer at sea level reads 400e and l200C when placed in pure melting ice and steam from

boiling water respectively. Determine the actual temperature when the thermometer reads 50°C. (2 marks)

12. An immersion heater rated at 180W is placed in a liquid of mass 2kg. When the heater is switched on for 7.5

minutes the temperature of the liquid rises by 40°C. Find the specific heat capacity of the liquid. (3 marks)

13. A car is carrying a luggage on its top. Explain what happens to the stability of the car after the luggage

accidentally falls off (1 mark)

SECTION II (55 marks) 14. a) State the principle of conservation of linear momentum (1 mark)

b) Calculate the recoil velocity of a gun of mass 0.4kg which fires a bullet of mass 0.0045 kg at a velocity of

400ms-1 (3 marks)

c) i) State two factors which affect frictional force on a body. (2 marks)

ii) State three ways in which friction can be minimised. (3 marks)

iii) State three advantages of friction. (3 marks)

15. a) Differentiate between heat capacity and specific heat capacity of a substance. (1 mark)

b) Briefly describe an experiment to determine the specific heat capacity of a liquid substance using the

electrical method. (6 marks)

c) An immersion heater rated 1000 W is used to heat a block of ice of mass 500g initially at -10°C until all the

water evaporates at 95°C. Assuming that the heat supplied is used to heat the ice, calculate the time in

minutes for the whole process to take place. (Take specific heat capacity of water as 4200Jkg-1 /0C specific

heat capacity of ice= 2100JKg-1kg-1

Specific latent heat of fusion = 3.35 X 105 J/kg

Specific latent heat of vapourisation = 2.2 x 105J/kg (5 marks)

16. a) i) State the Archimedes principle, (1 mark)

ii) An object weighs 1.04N in air 0.64N when fully immersed in water and 0.72N when fully immersed

in a liquid. If the density of water is 1000kgm-3, find the density of the liquid. (4 marks)

b) i) Define the law of floatation. (1 mark)

ii) Give a reason why a steel rod sinks in water while a ship made up of steel floats on water. (1 mark)

iii) The figure below shows a buoy, B, of volume 40 litres and mass 10kg. It is held in position in sea water

of density 1.04gcm-3 by a light cable fixed to the bottom so that ¾ of the volume of the buoy is

below the surface of the sea water

Determine the tension T in the cable (4 marks)

17. a) i) Define mechanical advantages of a machine. (1 mark)

ii) Define the velocity ratio of a machine. (1 mark)

b) A pulley system has two pulleys on the lower block and two pulleys on the upper block. The system is used

to lift a load of 6N using an effort of 2N.

i) Calculate the mechanical advantage of the system. (3 marks)

ii) Find the efficiency of the pulley system (3 marks)

iii) If the lower block weighs 0.4N, what friction force opposes the motion? (3 marks)

18. a) Define the following terms as used in motion:

i) Inelastic collision. (1mark) ii) Momentum. (l mark)

b) A bullet of mass 20g moving with a velocity of 1000ms-1 hits a stationery wooden block of mass

12kg. The bullet imbeds and the two move in one direction. Calculate its final velocity. (2 marks)

c) A block of mass 200g rests on a rough horizontal table. A force of 0.6N pulls the block so that it moves

with a constant acceleration of l ms-2

Calculate the time it takes to travels a distance of 200m. (3 marks)


232 / 2

PHYSICS Paper 2

Section A (25 marks)

Answer ALL the questions in this section in the spaces provided.

1. Fig 1 represents a pinhole camera

Sketch rays to show the formation of an enlarged image in the camera. Label both the object and the image.

(2 marks)

2. State one advantage of an alkaline cell over a lead-acid cell. (1 mark)

3. Fig 2 shows a horse-shoe magnet whose poles are labelled and two other magnets near it. Iron nails are attracted

to the lower ends of the magnetic as shown.

Identify the poles marked X and y. (1 mark)

4. Fig 3 shows the displacement time graph for a certain wave.

Determine the frequency of the wave. (3 marks)

5. In the circuit diagram shown in figure 4, the ammeter has negligible resistance. When the switch, S is closed, the

ammeter reads 0.13A

Determine the internal resistance of the cell. (3 marks)

6. Figure 5 shows a ray of light incident on the face of a water prism.

Sketch the path of the ray as it passes through the prism. Critical angle for water is 49°. (1 mark)

7. You are provided with a diode, a resistor R, an a.c. source of low voltage and connecting wires. In the space

provided, sketch the circuit diagram for a half-wave rectifiers and indicate the terminals where the output

voltage V0 may be connected. (2 marks)

8. The following is part of a radioactive decay series:

𝐵𝑖 𝑋 𝑌𝑏230

84𝑎

83234

Determine the values of a and b. (2 marks)

9. Fig 6 shows an object, O, in front of a concave mirror and its image I formed after reflection.

a) On the same diagram draw appropriate ray(s) to locate the principal focus, F, of the mirror. (2 marks)

b) Determine the focal length of the mirror (Scale 1 : 5) (1 mark)

10. In an x-ray tube it is observed that the intensity of X-rays increases when potential difference across the

filament is increased. Explain this observation. (3 marks)

11. An electromagnet is made by winding insulated copper wire on an iron core. State two changes that could be

made to increase the strength of the electromagnet. (2 marks)

12. Fig 7 shows a circuit in which a battery of negligible internal resistance, two resistors, capacitor, a voltmeter and

a switch are connected.

Giving a reason for your answer in each case, state the reading on the voltmeter, V, when the switch is

i) Open ii) Closed

13. a) State Lenz’s law of electromagnetic induction. (1mark)

b) Fig 8 shows a simple microphone in which sound waves from the person talking cause the cardboard

diaphragm to vibrate

𝛽

i) Explain how a varying current is induced in the coil when the diaphragm vibrates. (3 marks)

ii) State two ways in which the induced current in (i) above can be increased. (2 marks)

c) A transformer with 1200 turns in the primary circuit and 120 turns in the secondary circuit has its primary

circuit connected to a 400V a.c. source. It is found that when a heater is connected to the secondary circuit,

it produces heat at the rate of 600W. Assuming 100% efficiency, determine the:

i) Voltage in the secondary circuit. (2 marks)

ii) Current in the primary circuit (2 marks)

iii) Current in the secondary circuit. (2 marks)

14. a) Figure 9 shows the features of a cathode ray tube

i) Name the parts labelled A and B. (2 marks)

ii) Explain how the electrons are produced in the tube. (2 marks)

iii) State two functions of the anodes. (2 marks)

iv) At what part of the cathode ray tube would the time base be connected? (1 mark)

v) Why is a vacuum created in the tube? (1 mark)

b) The graph in figure 10 below was obtained on a cathode ray oscilloscope (CRO) screen when the output of

an a .c. generator was connected to the input of the CRO. The time-base calibration was set at 20

milliseconds per cm and y-gain at 5 volts per cm.

i) Determine the pick voltage of the generator. (2 marks)

ii) Determine the frequency of the voltage. (3 marks)

iii) On the same grid, redraw the graph for the same voltage when the time base calibration is

set at 40 milliseconds per centimeter and the y-gain at 10Volts per centimetre

(show at least one complete cycle) (2 marks)

15. a) Figure 11 shows a section of a house wiring system.

i) Name:

The circuit labelled P. (1 mark)

I. What is the purpose or R in the circuit?

(1 mark)

II. Give a reason why R is connected to Y but not to

X. (1 mark)

III. Why is the earthing necessary in such a circuit?

(1 mark)

a) Determine the cost of using an electric iron rated

1500W for a total of 30 hours given that the cost

or electricity per unit is kshs 8. (2 marks)

16. a) The figure below shows a circuit diagram for a photocell.

i) Explain why the milliammeter shows a

deflection when UV-light is shown on the

photocell. (3 marks)

ii) Explain how the milliammeter reading is

affected, when the intensity of light in increased.

(2 marks)

iii) Give one use of photocell. (1 mark)

b) In an experiment to observe photoelectric emission from a clean zinc surface, the following readings

were obtained.

Stopping potential (Volts) 0.6 1.0 1.4 1.8 2.2

Frequency (x 1014 Hz) 6.0 7.0 8.0 9.0 10.0

i) Plot a graph of stopping potential Vs (y - axis) against frequency, (5 marks)

ii) From the graph, determine the threshold frequency or the surface. (l mark)

iii) Use the graph to determine Plank's constant (charge on electron. e = 1.6 x 1O-19C) (3 marks)

17. a) Define the term virtual image as a applied in lenses. (2 marks)

b) You are provided with the following:

Convex lens, a screen, a candle and a metre rule.

i) Sketch the diagram of the set-up that can be used in determining the focal length. (2 marks)

ii) State the measurements that would be taken. (2 marks)

iii) Explain how these measurements would be used in determining the focal length of the lens. (3 marks)

c) A small vertical object is placed 9cm from a converging lens of focal length 10cm. Determine the nature of

the image formed and the distance of the image from the lens. (4 marks)



232 /3

PHYSICS Paper 3

(Practical)

1. You are provided with the following items

Clamp, boss and stand.

Optical pin fixed on a

piece of cork

Copper wire of length

40cm

Protractor

Stop watch

Pliers (can be shared)

Proceed as follows:

a) Bend the wire in the middle so that the angle formed is 200.

b) Set up the apparatus as shown in figure 1.

c) Displace the wire horizontally and allow it to swing freely. Record time for 10 complete oscillations.

t = _________________________seconds. (1 mark)

d) Repeat the procedure above for the other given angles on the table below.

Angle 𝛼 Time for 10 oscillations t(sec) f = t/2 f2 (Hz)2 𝛼

2 Cos

𝛼

2

20o

40 o

60 o

80 o

100 o

(7 marks)

e) On the grid provided, plot a graph of f2 (Hz)2 against Cos 𝛼

2 (5 marks)

f) Determine the gradient of the graph. (3 marks)

g) Given the equation f2 = 2

37.5

y

cos

𝛼

2, use the graph to determine the value of if y is the total length of the

wire in centimetres. (3 marks)

Question 2


- A voltmeter (0 - 3V) - 100cm wire mounted on a millimetre scale

labelled w.

- A switch

- Two new dry cells.

- Eight connecting wires, 4 with crocodile

clips.

- A jockey

- A cell holder.

- A micrometer screw gauge (can be shared)

Proceed as follows

a) Connect up the circuit as shown in the figure 2.

b) Using the jockey, J, place it on the wire W so that the length QR = 80cm. Close the switch quickly and record the

value of the voltmeter reading and then open the switch.

c) Repeat the experiment with values of l = 70cm, 60cm, 50cm, 40cm, 30cm and 20cm. Record and complete the

table of values below.

m 80 70 60 50 40 30 20

V (v) I/l (metres)-1 I/V (V)-1

(6 marks)

d) Plot a graph, of I/V (V)-1 against I/l (m)-1 (5 marks)

e) From the graph determine the slope of the graph. (3 marks)

f) Using the micrometer screw gauge, measure the diameter, D of the wire.

D = __________________________________mm (1 mark)

g) Determine the cross-section area, A of the wire in m2 (2 marks)

h) Given that 1

𝑉=

𝐴𝑋

10−6𝐸 (

1

𝐼) +

1

𝐸, use the graph to determine x (3 marks)

KAJIADO JOINT EVALUATION TEST, 2013

Kenya Certificate of Secondary Education(K.C.S.E)

232 / 1

PHYSICS

Paper 1

SECTION A: (25 Marks)

1. The figure 1.0 below shows a section of a burette.

Indicate the new reading on the burette when a steel ball of a volume 4cm3 is placed in the burette. (2 marks)

2. Figure 2.0 below shows a block of wood resting on an inclined plane.

Indicate on the same diagram the forces acting on the block. (3 marks)

3. Fig. 3 below shows a candle balanced on a knife edge.

It is lit on side A.

a) State the observation made after some time. (1 mark)

b) Explain the observation made in (a) above. (1 mark)

4. An oil drop of diameter 2.1mm is placed on the surface of water in a basin. It spreads to form a patch of diameter

30cm. Determine thickness of the oil molecule. Give your answer in SI units and in standard form. (4 marks)

5. Figure 4 shows a U-tube containing liquid A of density 1.25g/cm3 and a liquid B.

Determine the density of liquid B. (3 marks)

6. The graph below is a graph of the force against extension in compressing of a spring.

Determine the work done is compressing the spring by 20mm. (3 marks)

7. A frying pan hangs freely from a nail fixed on the wall. What is the state of equilibrium of the frying pan? (l mk)

8. The figure 6 shows the graph obtained when an experiment to investigate the relationship between pressure and

volume of a certain gas.

State two precautions to be taken into account while performing the experiment. (2 marks)

9. A stone is projected vertically upwards with a velocity of 12m/s. Determine the velocity of the stone at the height

of 3.6m.(Take g = 10m/s2) (3 marks)

10. Thermometer A is wrapped with a cotton wool that has been soaked in methylated spirit and thermometer B is

also wrapped in cotton wool soaked in water. They are both placed in the same room.

a) State which thermometer reads a higher temperature. (1 mark)

b) Give a reason for your answer in a above. (1 mark)



11. You are provided with the following apparatus to determine the density of lead.

- Density bottle

- Lead shots

- Beam Balance

- Water

a) Write down the measurements that would be taken (4 marks)

b) From the measurements above explain how you would determine:

i) Mass of lead shot. (1 mark)

ii) Volume of lead shot. (2 marks)

c) In terms of the readings taken above calculate the density of lead. (1 mark)

d) State two reasons why lead shots are used in this experiment. (2 marks)

12. The diagram below shows a steel falling through points X to Y.

a) i) Draw the forces experienced by the ball bearing and name them. (3 marks)

ii) From point X to Y the body acquires terminal velocity.

If XY measures 15cm and the body takes 2 seconds to fall through XY, determine the terminal velocity.

(2 marks)

b) i) State how terminal velocity is achieved. (1 mark)

ii) State how viscosity of a liquid depends on temperature. (1 mark)

c) The fig 8 below shows a pulley system used to raise a load. A force of 100N is used to raise a lead of 225N

Determine the efficient of the pulley system. (3 marks)

13. A solid of mass 500g is heated to a temperature of 960c and transferred into a calorimeter containing ice at a

temperature of -50c. The mixture acquires a final temperature of 520c. If the mass of the calorimeter and ice is

230g and the mas of empty calorimeter is 130g

Determine:

a) Mass of the ice. (1 mark)

b) Heat lost by metallic block. (5 marks)

c) Specific heat capacity of the metal block. (4 marks)

(Take: Specific heat capacity of ice = 2100J/KgK)

Latent heat of solution of ice = 336000J / kg

Specific Heat capacity of water = 4200 K / KgK

Specific Heat capacity of Copper = 400 J / KgJ

14. a) Distinguish between angular displacement and angular velocity. (1 mark)

b) The figure 9 below shows a mass moving on a horizontal plane.

i) State what is observed on mass B. (1 mark)

ii) Explain your answer. (2 marks)

c) i) The figure 10 below shows a boy of mass 50kg swinging on a rope of length 2m.

If the tension in the rope is 549N, calculate the velocity of the boy at the position shown in the

diagram. (3 marks)

ii) State the form of energy possessed by the body at positions A and B. (2 marks)

iii) The diagram below shows a spray gun.

Explain how it works. (4 marks)

15. a) State Archimedes’ principle. (1 mark)

b) The figure 12 below shows a body floating on a liquid.

Determine

i) The upthrust on the body. (3 marks)

ii) The mass of the body. (2 marks)

iii) Density of body. (3 marks)

iv) If the same piece of block is made to float in water what will be the length inside the water? (3 marks)

Take density of paraffin = 800Kg /m3, density of water = 1000kg/m3, g = 10m/s

KAJIADO JOINT EVALUATION TEST, 2013


232 / 2

PHYSICS

Paper 2

(Theory)

SECTION A: (25 marks)


1. In fig 1.0 below, the object was drawn using a scale of 1:200.

Using suitable rays locate the image formed on the screen. (1 mark)

b) Determine the size of the image. (1 mark)

2. Fig. 2.0 show three identical bulbs connected in a circuit.

Explain what happens when

a) S1 is closed while S2 and S3 are open. (2 marks)

b) S1 and S2 are closed while S3 is open. (2 marks)

3. When a highly negatively charged rod is brought slowly near the tap of a positively charged electroscope, it is

observed that the leaf initially falls and then raises. Explain this observation. (3 marks)

4. Fig 3.0 shows two bar magnets placed with North poles close together.

Sketch the magnetic field patterns between the two North poles. (2 marks)

5. Fig 4.0 below shows a beaker placed over an ink mark. The beaker contains a block of glass of thickness 10cm.

Over this block is paraffin of depth 18cm.

Calculate

The vertical displacement of the ink.

[Refractive index of paraffin = 1.44, refractive index of glass block – 1.5] (3 marks)

6. Fig 5.0 below shows a circuit developed by a student.

i) State the observation made when the switch is closed. (1 mark)

ii) Explain the observation made in a) above. (2 marks)

7. A girl standing infront of a tall building blows a whistle and hears an echo after 1.5 seconds. She then Moves 51

meters farther away from the cliff and blows the whistle again. She now hears the echo after 1.8 seconds.

Determine the speed of the sound. (3 marks)

8. An x-ray tube produces x-rays of frequency 3.2 x 1019 Hz. Calculate the accelerating potential of the x-ray tube.

(Planck’s constant = 6.6 x 10-34 Js, electron charge = 1.6 x 10-19C) (3 marks)

9. State one method which can be used to change direction of cathode rays. (1 mark)

10. Explain the difference you would expect to find between the wiring used to connect the bulb and the water heater

to the mains supply. (1 mark)



11. a) Name the device that converts light energy directly into electrical energy. (1 mark)

b) The graph below shows values of stopping potentials against frequency.

From the graph determine:

i) Threshold frequency. (1 mark)

ii) The gradient of the graph. (3 marks)

iii) Planks constant. (Take electron charge e = 1.6 x 10-19C) (2 marks)

iv) Work function. (3 marks)

c) Light of frequency 5.5 x 1014 Hz is made to strike a surface whose work fraction is 2.5eV show that Photoelectric

will not take place. (Electron charge = 1.6 x 10-19C)

12. a) Give two differences between the eye and the camera. (2 marks)

b) In an experiment to determine the focal length of a converging lens, values of image distance v

corresponding to different values of object distance, u were determined.

A graph of (u + v) against uv was plotted as shown below

Frequency f x 1014(Hz)

Sto

ppin

g p

ote

nti

al V

s(V

)

i) Determine the gradient of the graph. (3 marks)

ii) Using the graph to determine the focal length of the lens. (1 mark)

c) Fig. 8.0 below shows an object placed 10cm infront of a convex lens of focal length 15cm. Scale 1 : 2

i) Construct a ray diagram to show the position of the image formed. (3 marks)

ii) Determine the position of the image formed. (2 marks)

13. a) A radioactive isotope has a half-life of 5.3 years. Explain what is meant by half-life. (1 mark)

b) 208g of sodium -24 decays to 13g within 60 hours. What is the half-life of this isotope? (3 marks)

c) What is background radiations? (1 mark)

d) Aluminium is rolled into sheets 20mm thick in a rolling mill. A radioactive source and a detector are used to

check the thickness of the sheet as it leaves the roller.

i) Why is beta radiation not suitable for checking the thickness of the sheet. (1 mark)

ii) Suggest one type of radiation which would be used to check the thickness of the 20mm sheet. (1 mark)

e) Fig 9.0 shows a Griger Muller tube

i) Label parts A and B. (2 marks)

ii) Explain how the radiations entering the tube through the window are detected by the tube. (3 marks)

14. You are provided with the following; switch, voltmeter, ammeter, rheostat, cell and connecting wires.

a) Draw a circuit that can be used to determine the internal resistance of the cell. (1 mark)

b) Explain how the circuit can be used to determine the internal resistance of the cell. (4 marks)

c) Fig 10.0 below shows a current of 2A flowing through two resistors connected as shown.

Find the potential difference across the 8Ω resistor. (3 marks)

d) Fig 11.0 below shows three capacitors connected in a circuit.

Calculate the charge stored by the 4µf capacitor. (4 marks)

15. A thermistor TH is connected in parallel with a bulb as shown in fig 12.0 below, the bulb is lit. When the

Thermistor is steadily heated; the brightness of the bulb reduces.

Explain the observation (2 marks)

b) Explain how doping produces a P- type semi- conductor. (3 marks)

c) Fig 13.0 shows a circuit a rectifier using four diodes, D1, D2, D3, and D4

Explain how a rectified output is produced from the set up when an a.c input is connected across AB.

(3 marks)

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