UNEB UCE PHYSICS PAPER 1 Nov./Dec. 1997

SECTION A

1. Which of the following groups consists of vectors only?

A. momentum, acceleration, work, energy

B. speed, velocity, displacement, energy

C. displacement, velocity, acceleration, force

D. velocity, work, power, momentum

2. The figure shows a speed-time graph for a body.

Calculate the distance traveled during retardation.

A. 20m B. 40m C. 80m D. 100m

3. A balloon is filled with hydrogen and released in the open air. It will rise

A. to a certain height and then float

B. to a certain height and then drop

C. to a certain height and then burst

D. indefinitely

4. A man runs a race against a dog. The distance-time graph for the race is shown below.

Which of the following statements are true?

1. the dog’s time for the race was 6s.
2. the dog overtook the man 9.6s after he had started running.
3. the man’s speed did not change after 6s.
4. the dog ran a shorter distance than the man.

A. (i), (ii) and (iii)

B. (i) and (iii) only

C. (ii) and (iv)

D. (iv) only

5. Liquid Y of volume 0.40m³ and density 900kgm^-3 is mixed with liquid Z of volume 0.35m³ and density 900kgm^-3. Calculate the density of the mixture.

A. 800kgm^-3 B. 840kgm^-3 C. 850kgm^-3 D. 900kgm^-3

6. A boy throws a ball in the air and it goes up and falls back to his hand. Which one of the following sketches of velocity-time graph represents the motion of the ball up to the time it is received back?

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7. A force of 10N acts on a body and produces an acceleration of 2ms^-2. The mass of the body is

A. 0.2kg B. 5.0kg C. 20.0kg D. 50.0kg

8. Which of the following statements is true about an electric motor? It changes

A. kinetic energy to electric energy

B. electrical energy to light energy

C. electrical energy to kinetic energy

D. chemical energy to electrical energy

9. A body pulls a block of wood with a force of 30N through a distance of 300m in 2 minutes. Find the power he develops, if he pulls the block at a constant speed.

1. B.
2. C.
3. D.

10. A ball of 1kg bounces off the ground to a height of 2m after falling from a height of 5m, find the energy lost.

A. 5 J B. 20 J C. 30 J D. 50 J

11. Which of the following is true about pressure in liquids? It

A. increases with the surface area of the liquid

B. is directly proportional to the depth

C. depends on the shape of the container

D. is the same at equal depths in all liquids

12.

The diagram in the figure above shows a mercury barometer. What is the value of the atmospheric pressure?

A. 74cm B. 76cm C. 77cm D. 79cm

13. When smoke is introduced in a smoke cell and observed under a microscope, it is observed as particles moving at random. This is mainly because the particles

A. are hot

B. collide with one another

C. collide with air molecules

D. collide with the walls of the smoke cell

14. Which of the following changes occur when a metal block is heated?

15. Calculate the specific heat capacity of paraffin if 22000 joules of heat are required to raise the temperature of 2.0kg of paraffin from 20°C to 30°C.

A. 1100 J kg^-1K^-1 B. 1200 J kg^-1K^-1

C. 2200 J kg^-1K^-1 D. 2100 J kg^-1K^-1

16. Which of the following can produce a cooling effect?

(i) compression of a gas

(ii) expansion of a gas

(iii) evaporation of a liquid

A. (i), (ii), (iii)

B. (i) and (iii) only

C. (ii) and (iii) only

D. (iii) only

17. The distance between the lower and upper fixed points on the Celsius in an unmarked mercury in-glass thermometer is 25cm. If the mercury level is 5cm below the upper fixed point, then the temperature is

A. 50°C B. 20°C C. 80°C D. 95°C

18. What is the process by which electrons are emitted from a hot filament?

A. radioactivity

B. nuclear reaction

C. thermionic emission

D. thermo-electric effect

19. A load of 4N stretches a spring by 0.5cm. Calculate the extension when a load of 8N is applied.

A. 0.25cm B. 1.0cm C. 2.0cm D. 4.0cm

20. Which of the following statements are true?

(i) protons and neutrons are found in the nucleus of an atom

(ii) electrons and beta particles are the same

(iii) protons and electrons occur in equal numbers in all neutral atoms

(iv) alpha particles and beta particles are both positively charged.

A. (i), (ii) and (iii)

B. (i) and (iii) only

C. (ii) and (iv) only

D. (iv) only

21. A vibrator produces waves which travel a distance of 12m in 4s. If the frequency of the vibrator is 12Hz, what is the wavelength of the waves?

A. 1.5m B. 3m C. 6m D. 24m

22. A pin-hole camera, sharper and taller images are obtained by

A. widening the hole and moving the object farther

B. narrowing the hole and moving the object nearer

C. using a longer camera with a wider hole

D. using a shorter camera with a narrower hole

23. A girl stands between two tall cliffs and claps her hands. She hears the first echo after 1s and the second echo after 2s. If the speed of sound is 300ms^-1, the distance between cliffs is

A. 300m B. 450m C. 900m D. 1200m

24.

A person observes the image of a pin placed in front of a plane mirror as shown in the figure above. The reflected beam from the pin reaching the observer is a

A. virtual beam B. divergent beam

C. parallel beam D. convergent beam

25. Which of the following is a correct ray diagram?

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26. Which of the following statements is true?

A. light waves, radio waves and sound waves will travel through a vacuum

B. light waves and radio waves will travel through a vacuum, sound waves will not.

C. light waves and sound waves will travel through a vacuum, radio waves will not.

D. sound waves and radio waves will travel through a vacuum, light waves will not.

27. An object is placed at a distance of 20m from a convex lens of focal length 15cm. The type of image formed is

A. inverted and magnified

B. inverted and diminished

C. upright and diminished

D. upright and magnified

28. Which of the following statements is true about a good insulator?

A. it acquires electric charge when rubbed with suitable materials

B. all its electrons are loosely bound to its atoms

C. electric charge easily flows on its surface

D. some of its electrons are free to move about

29. Four metals P, Q, R and S are tested for magnetism. Q attracts both P and R but not S. S does not attract P, Q or R. P and R sometimes attract one another and sometimes repel each other. Which of the following statements is correct about P, Q, R and S?

A. P, Q, R are magnets, S is magnetic

B. P and Q are magnets, S and R are magnetic.

C. P and R are magnets, Q is magnetic, S is non-magnetic.

D. P and R are magnets, Q and S are non-magnetic.

30.

A battery of e.m.f. 12 V is connected across two resistors of 6 Ω and 3 Ω as shown in the figure. Which of the following statements is true about the circuit?

A. p.d across 6 Ω is half the p.d across 3 Ω

B. p.d across 6 Ω is twice the p.d across 3 Ω

C. p.d across 6 Ω is equal to p.d across 3 Ω

D. reading of the voltmeter V is greater than 12V

31.

The diagram in the figure above shows a current carrying coil PQRS pivoted at about XY between two magnets. Which of the statements are true about the coil? The sides PQ and QR shall experience force.

1. As seen from X, the coil will rotate anticlockwise.
2. The force on the coil can be increased by increasing the number of turns.
3. The coil will come to rest with PQ at right angles to magnetic field.

A. (i), (ii) and (iii)

B. (i) and (iii) only

C. (ii) and (iv) only

D. (iv) only

32. An electric heater is immersed in 0.05kg of oil in a calorimeter of negligible heat capacity. The temperature of the oil rose from 20°C to 50°C in 100s. If the specific heat capacity of the oil is 2000 J kg^-1K^-1, calculate the power supplied by the heater, assuming that there is no heat loss.

A. 30W B. 50W C. 140W D. 600W

33. Sound waves

A. do not pass through a vacuum

B. travel through solids at lower speed than in air

C. do not travel through liquids

D. travel at highest speed in air.

34. An electric heater which operates from 240V mains draws 15A for 40 minutes. Calculate the cost of electricity, given that electricity costs 9.00 per kilowatt hour.

A. sh.1.44 B. sh.21.60 C. sh.960 D. sh.1296

35. Two coils of wire of resistances 2Ω and 3 Ω are connected in series to a 10V battery of negligible internal resistance. The current through the 2Ω resistor is

A. 0.5 A B. 2 A C. 5 A D. 50 A

36. Which one of the following does not change when water waves travel from deep to shallow water?

A. frequency B. amplitude C. velocity D. wavelength

37. A bulb of resistance 1.5Ω is connected to a cell of e.m.f. 2.0V. Find the energy dissipated in 45s.

A. 60 J B. 67.5 J C. 90 J D. 120 J

38. Element X emits radiation R and forms element Y as given in the equation:

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While A and Z are mass and atomic numbers respectively, radiation R is

A. alpha particles B. beta particles

C. gamma rays D. X-rays

39. An electroscope becomes negatively charged when it

A. loses electrons B. gains protons

C. gains electrons D. loses protons

40. The half-life of a radioactive element is 4 hours. Find the mass of the element that decays after 24 hours if the initial mass is 9.6g.

A. 0.15g B. 1.6g C. 9.45g D. 4.8g

SECTION B

1. (a) (i) State the principle of moments.

(ii) State the conditions for a body to be in equilibrium.

(b) What is meant by centre of gravity?

2. (a) State Archimedes’ principle.

(b) A rubber balloon of mass 5×10^-3kg is inflated with hydrogen and held stationary by means of a string. If the volume of the inflated balloon is 5×10^-3m³, calculate the tension in the string. (Density of hydrogen = 0.080 kg/m³, density of air = 1.150 kg/m³).

3. (a) Explain why gaps are left between rails in a railway line.

(b) Why do gases expand much more than solids for the same temperature change?

(c) Name one application of a bimetallic strip.

4. (a) Define specific heat capacity.

(b) An immersion heater rated 1000W, 250 V supplies heat to 80kg of liquid in a tank. If the temperature of the liquid rises by 40°C in 48 minutes, what is the specific heat capacity of the liquid?

5. A man whose mass is 75kg climbs up a ladder of 6.5m high in 5s. Calculate the

1. work done
2. power expended

6.

The diagram in the figure shows a section of a transverse wave of wavelength 4.0cm.

Find its (i) frequency

(ii) amplitude

(iii) velocity

7. (a) State the laws of refraction.

(b) In the diagram above, an object O is placed at the bottom of a clear pond. Draw rays to show how the object appears to an observer at E.

8. (a) What is a radioactive nuclide?

(b) A radioactive element X decays by emitting an alpha particle and gamma rays. Write a balanced equation for the decay.

(c) State what happens to a beta particle as it passes between two oppositely charged plates.

9. (a) Why is an ammeter constructed such that it has a long internal resistance?

(b) A milliammeter has an internal resistance of 4Ω and a full scale deflection of 0.015 A. Calculate the value of the resistor that must be connected to the milliammeter so that a maximum current of 5A can be measured.

10. (a) What is a transformer?

(b) A transformer whose efficiency is 80% has an output of 12W. Calculate the input current if the input voltage is 240V.

(c) Explain briefly why bulbs in a building are connected in parallel.

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