1999

## SECTION A

1. Find the force required to give a mass of 500g an acceleration of 2 x 10-2 ms-2.

A. 1 x 10-2 N. B. A. 1 x 10-1 N.

C. A. 1 x 102 N. D. A. 1 x 104 N.

2. The graph in figure 1 describes the motion of particle. Between which points is the particle at rest?

A. O and P. B. P and Q. C. Q and R. D. R and S.

3. Eggs packet in a soft, shock-absorbing box are placed in a car. When the car suddenly starts or stops moving, the eggs do not crack because

A. no force acts on them.

B. the force acts on them for only a short time.

C. the force is small and acts for longer time.

D. the force causes fast change of momentum.

4. When a spherical ball falls through a column of oil with a steady velocity, the total

A. downward force is greater than total upward force.

B. upward force is greater than total downward force.

C. upward force is equal total downward force.

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D. upward force is zero.

5. A uniform metre-rule is pivoted at its centre as shown in figure 2.

If the rule is in equilibrium, find the value F.

A. 4N B. 33.3N C. 50N D. 100N

6. The shaft in an engine is subjected to two parallel but opposite forces of 500N each as shown in figure 3.

The rotation is best stopped by applying

A. two forces of 500N acting at right angles to each other.

B. two parallel but opposite forces of 500N.

C. a single force of 100N.

D. a single force of 250N.

7. A bullet of mass 0.02kg is fired with a speed of 40m s-1. Calculate its kinetic energy.

A. 0.4J. B. 0.8J. C. 16J. D. 32J.

8. The energy changes that take place when a stone falls freely from rest to the ground can be orderly arranged as:

A. Kinetic energy è Potential energy è Sound energy è Heat.

B. Sound energy è Potential energy è Kinetic energy è Heat.

C. Potential energy è Sound energy è Kinetic energy è Heat.

D. Potential energy è Kinetic energy è Heat energy è Sound.

9. A dull black surface feels hotter even through it is at the same temperature as a shiny surface because it

A. has more heat than a shiny surface.

B. emits more heat than a shiny surface.

C. reflects more heat than a shiny surface.

D. conducts more heat than shiny surface.

10. An electric heater is rated 240V, 400W. if the efficiency of the heater is 80% find the amount of energy wasted per second.

A. 48J. B. 80J. C. 192J. D. 320J.

11. Which one of the following statements is false? The pressure in a liquid

A. at any one point in liquid would not change even when more liquid is added.

B. at any one point depends only on the depth and density.

C. at any one point acts equally in all directions.

D. increases with depth.

12. The following readings were recorded when measuring the density of a stone:

Mass of stone = 25g Volume of water = 25cm3, Volume of water and stone = 35cm3.

What is the density of the stone?

A. 25/10 g cm3 B. 35/30 g cm3 C. 10 g cm 3 D. 25/35 g cm3

13. Water wets glass because

A. adhesion forces between water and glass molecules are less than cohesion forces

B. adhesion forces between water and glass molecules are more than cohesion forces

C. surface tension forces between water and glass molecules are more than adhesion forces

D. surface tension forces are less than cohesion forces.

14. In a Brownian motion experiment, the

A. smoke particles are seen moving about with uniform velocity.

B. motion observed is caused by the air molecules colliding with the smoke particles.

C. size of particles are found to increase the motion.

D. smoke cell has a vacuum within it.

15.

The graph in figure 4 shows a cooling curve of a pure substance. The substance is all in solid state between

A. W and X. B. W and Y. C. X and Y. D. Y and Z.

16. A bimetallic strip operates on the principle that metals

A. are heat controllers. B. are good heat conductors.

C. have different rates of expression. D. have the same rates of expression.

17.

17.

In figure 5, a fixed mass of dry air is trapped in bulb A. Calculate the total pressure of the air in A, given that atmospheric pressure is 76 cm of mercury.

A. 30 cm Hg. B. 38 cm Hg.

C. 46 cm Hg. D. 114 cm Hg.

18.

The diagram in figure 6 shows a framework of a bridge. Which of the girders are ties?

A. XQ, QY, PX, YR B. PQ, QR, XY C. XQ, QY D. PX, YR

19. Which of the following are all brittle materials?

A. Leather, rubber, thread. B. Clay, glass, wood.

C. Glass, cast iron, stone. D. Rubber, polyester, copper wire.

20. Which one of the following are properties of Cathode rays?

(i) The travel in straight lines.

(ii) They can penetrate a thick sheet of paper.

(iii) They darken a photographic plate.

(iv) They are deflected by a magnetic field.

A. (i), (iii) and (iv) only. B. (i), (ii) and (iv) only.

C. (i), (ii) and (iii) only. D. (iv) only.

21. The cathode ray oscilloscope may be used to

(i) measure energy.

(ii) measure potential difference.

(iii) display wave forms.

A. (i) only. B. (i) and (ii) only.

C. (ii) and (iii) only. D. (i), (ii) and (iii).

22. Which of the following represents an appearance on the screen of a cathode ray oscilloscope when a d.c. voltage is connected across the Y-plates with the time-base switches on?

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23. Thorium has a half-life of 24days. How many days would it take 8 kg of thorium to disintegrate to 1g?

A. 3 B. 24 C. 72 D. 96

24.

The table above shows readings obtained by using a vibrator which produces waves of a constant velocity. Find the frequency of the wave Q.

A. 0.07MHz. B. 0.3 MHz. C. 0.6 MHz. D. 1.2 MHz.

25. Which of the following are transverse waves only?

A. Radio, sound, ultra-violet. B. ultra-violet, x-rays, water waves.

C. Infrared, gamma rays, sound wave. D. Sound waves, ultra-violet, X-rays.

26. A boy standing 150 m from a vertical cliff claps his hands and hears an echo 0.85 seconds later. Find the speed of sound in air.

A. 128 m s-1 B. 176 m s-1 C. 255 m s-1 D. 353 m s-1

27. In a sound wave the particles of the medium

A. are stationary.

B. move along with the wave.

C. vibrate in the same direction as the wave.

D. vibrate at right angles to the direction of the wave.

28.

Objects P and Q are placed at distances of 2 m and 3 m respectively from a plane mirror as shown in figure 7. find how far the image of P is from Q.

A. 1m. B. 4m. C. 5m. D. 7m.

29.

Figure 8 shows white light passing through a glass prism. Which colour is bent most?

A. Red. B. Yellow. C. Green. D. Violet.

30. Which one of the following is a properties of X-rays?

A. They can deflected by magnetic field.

B. They can ionise matter.

C. They can cause photo-electric emission.

D. They can electrically charged particles.

31. A body can only be confirmed to be electrically charged when

A. another charged body attracts it.

B. it does not affect the leaf of a charged elecroscope.

C. it is repelled by another charged body.

D. it is found to have less protons than electrons.

32. Which of the following shows a correct electric field pattern due to two charges?

33. Which of the following will increase the force on a current carrying wire?

(i) Using a large current.

(ii) Using a stronger magnetic field.

(iii) Using a shorter length of wire in the field.

A. (i) only. B. (i) and (ii) only.

C. (i) and (iii) only. D. (ii) and (iii) only.

34.

In figure 9 above name the polarities P and Q.

35.

Figure 10 shows a network of resistors. The effective resistance between points P and Q is

A. 0.97Ω. B. 1.2Ω. C. 2.5Ω. D. 10Ω.

36. A car head lamp bulb is marked 12V, 48W. This means that when a

A. voltage of 12V is applied, a current of ¼ A flows.

B. power of 48W is developed, the resistance is 4Ω.

C. voltage of 12 V is applied, resistance is Ω.

D. voltage of 12 V is applied, energy used in every second is 48J.

37. A transformer is used to step down an alternating voltage from 240V to 12V. Calculate the number of turns on the secondary coil if the primary coil has 1200 turns.

A. 3. B. 5. C. 60. D. 100.

38. Which of the following graphs represents the output voltage from a d.c. dynamo?

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39. Which of the following statements are true about electric wiring?

(i) The fuse is always connected into the live wire leading to circuit.

(ii) The fuse is connected into the neutral wire leading to a circuit.

(iii) When a fault develops in the circuit, it is the neutral wire which has to be disconnected.

A. (i) only. B. (iii) only. C. (i) and (iii) only. D. (i), (ii) and (iii).

40. An electricity board charges shs 10 per kilowatt-hour of electrical energy supplied. What is the total cost in shs. Of operating 4 light bulbs, each rated at 100W for 5 hours?

A. Sh2. B. Sh.20. C. Sh 4,000 D. Sh 20,000

## SECTION B

1. An object is released from rest at a height of 20 m above the ground.

(i) describe the energy changes which take place.

(ii) Calculate the speed with which the object hits ground.

2. (a) Define Power.

(b) Find the power developed when a crane lifts a load of 3500N through 5m in 5s.

3. (a) Define Moment of a force.

(b) A uniform metre-rule is balanced at the 30-cm mark when a load of 0.8 N is hang at the zero-mark. Find the weight of the metre-rule.

4. (a) The specific heat capacity of water is 4200 J kg-1 k-1. What is meant by the above statement? (b) State two reasons why water is used in the cooling system of a car engine?

(c) What is the use of a vacuum in a thermos flask?

5. (a) Give two observations which show the existence of surface tension.

(b) State two factors which affect surface tension of a liquid.

6. The symbol 235 92U denotes a uranium nucleus.

(a) What is the meaning of

(i) 235?

(ii) 92?

(b) Write down a balanced nuclear equation showing the decay of 235 92U to a nuclide X by emission of an alpha particle.

7. (a) What is meant by a standing wave?

(b) figure 11 shows plane waves approaching a gap in a barrier.

(i) Show the diagram, the appearance of the waves after the barrier.

(ii) what is the effect of reducing the size of the gap?

8. (a) Sketch a diagram to show the formation of a solar eclipse.

(b) The refractive index of a glass block is 1.62. Calculate its critical angle.

9. (a) State the laws of electrostatics.

(b) Two insulating materials are rubbed together describe what is observed if

(i) the two are brought near the cap of a gold leaf electroscope.

(ii) only one of them is brought near the cap.

(c) why is it difficult to perform experiments in electrostatics under damp conditions?

10. A galvanometer has resistance of 5Ω and a range of 0-40mA. Find the resistance of the resistor which must be connected in parallel with the galvanometer if a maximum current of 10 A is to be measured.

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