UNEB UCE PHYSICS PAPER 1 Nov./Dec. 1998

SECTION A

1. In which of the following situations is maximum frictional force required?

• A. Sliding down a slope
• B. Walking along a road
• C. Leaning a ladder against a wall
• D. Designing brake blocks for a bicycle

2.

Which of the distance-time graphs above represents a body retarding?

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3. A water pump rises 2000 kg of water through a vertical height of 72 m in one hour. Calculate the power of the pump.

• A. 40000 W
• B. 4000 W
• C. 400 W
• D. 40 W

4. A body of mass 20 kg moves with a uniform velocity of 4 m/s from rest. Find its momentum.

• A. 5 kg·m/s
• B. 80 kg·m/s
• C. 160 kg·m/s
• D. 320 kg·m/s

5. A car starts from rest and accelerates uniformly at the rate of 2 m/s² from ¼ of a minute. Find the velocity of the car after this time.

• A. 0.5 m/s
• B. 12 m/s
• C. 15 m/s
• D. 30 m/s

6. Calculate the effort when a load of 72 N is raised using a block system of 5 pulleys and efficiency 80%.

• A. 11.52 N
• B. 18 N
• C. 57.6 N
• D. 288 N

7.

In the above figure, the piston is moved from X to Y at constant temperature. The air pressure is:

• A. Trebled
• B. Doubled
• C. Reduced by a third
• D. Unchanged

8. In order to make a mercury thermometer more sensitive, the:

• A. Degree markings must be further apart
• B. Diameter of capillary tube must be reduced
• C. Volume of the mercury bulb must be reduced
• D. Capillary tube must be open to air

9. A tank of 2 m tall and base of 2.5 m² is filled to the brim with a liquid which exerts a force of 40000 N at the bottom. Calculate the density of the liquid.

• A. x 2 x 10 kg/m³
• B. x 2 x 10 kg/m³
• C. x 2 x 10 kg/m³
• D. x 2 x 10 kg/m³

10.

The above figure shows a crank of a bicycle pedal. The force a cyclist exerts on the pedal varies from a minimum to maximum. When does the cyclist exert maximum turning effort?

• A. Crank makes 90⁰ with the foot push
• B. Crank makes 0⁰ with the foot push
• C. Cyclist is climbing a hill
• D. Cyclist is turning a corner

11.

The above figure shows a spot on the screen of a cathode ray oscilloscope. The spot can be turned in a horizontal straight line as shown in (b) by:

• A. Switching off the time base
• B. Switching on the time base
• C. Making one of the plates positive
• D. Connecting an a.c voltage to the Y-plates

12. Which of the following are true statements about friction?

1. It does not oppose motion
2. It causes wearing of surfaces
3. It decreases as weight of the body increases
4. It can be reduced by applying oil between surfaces

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

13. A tight bottle top becomes easier to unscrew when hot water flows over it because the:

• A. Cap expands more than the glass
• B. Glass in the neck of the bottle contracts
• C. Hot water acts as oil between the glass and the bottle
• D. Increased pressure of the air in the bottle causes the cap to expand

14. A beam may be designed with much of its central part removed in order to improve on its:

• A. Brittleness
• B. Stiffness
• C. Ductility
• D. Stability

15. The temperature at which all heat energy is removed from a substance is called:

• A. Kelvin temperature
• B. Celsius temperature
• C. Freezing temperature
• D. Absolute zero temperature

16. The pressure of a fixed mass of a gas at 17⁰C is 10⁵ Pa. Find the pressure at 27⁰C if volume remains constant.

• A. x 10⁵ Pa
• B. x 10⁵ Pa
• C. x 10⁵ Pa
• D. x 10⁵ Pa

17.

A mass attached to the end of a string moves up and down to maximum and minimum points X and Y as shown in the above figure. When the mass is at X the:

• A. Kinetic energy is maximum, potential energy is minimum
• B. Kinetic energy is zero, potential energy is maximum
• C. Kinetic energy is equal to potential energy
• D. Kinetic energy and potential energy are both zero

18. Which of the following physical properties changes when a body is moved from the earth to the moon?

• A. Mass
• B. Volume
• C. Weight
• D. Density

19. Which of the following statements is true about the wave travelling from one medium to another?

1. Its frequency and wavelength change
2. Its frequency and velocity change
3. Its velocity and wavelength change
4. Only the frequency remains unchanged

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

20. Which of the following statements are true?

1. Surfaces which reflect all colours of light appear white
2. Red surfaces absorb all colours and reflect only red light
3. Black surfaces appear black because they reflect all colours

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

21. A possible isotope of Li has:

• A. Two protons and three neutrons
• B. Two protons and four neutrons
• C. Three protons and four neutrons
• D. Four protons and three neutrons

22. The secondary colours of light are cyan, magenta and yellow. Which of the following sets of addition of colours of light will produce white light?

1. Cyan + blue and magenta + red
2. Cyan + red and magenta + green
3. Yellow + red and magenta + blue
4. Cyan + green and yellow + blue

• A. (i) only
• B. (ii) only
• C. (iii) only
• D. (iv) only

23. Water waves travel a distance of 36 cm in 6 s and the separation of successive troughs is 3.0 cm. Calculate the frequency of the waves.

• A. 2 Hz
• B. 12 Hz
• C. 18 Hz
• D. 72 Hz

24. An alternating current can be changed to a direct current by a:

• A. Transformer
• B. Moving coil galvanometer
• C. Dynamo
• D. Diode

25. Which of the following statements are true about sound waves?

1. They are longitudinal
2. They are transverse
3. They are produced by vibrations
4. They can travel through empty space

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

26. The figure below shows circular waves incident on a plane reflector. Which of the following patterns represents the reflected waves?

27. ²²⁸₉₀Th → ^A_ZX + alpha particle.

The above equation represents an activity in which thorium decays and emits an alpha particle. Find the value of Z.

• A. 88
• B. 89
• C. 91
• D. 92

28. It is easier to charge insulators than conductors because:

• A. The insulators don’t allow the charge to flow away but the conductors allow the charge to flow away
• B. The conductor retains the charge by conduction but the insulators release it to the atmosphere
• C. It is impossible to charge conductors under any condition
• D. Insulators just receive the charge from the atmosphere without being rubbed

29. Which of the following are not electromagnetic waves?

• A. X-rays
• B. Radar waves
• C. Microwaves
• D. Sound waves

30. White light is separated into its component colours due to:

• A. Absorption
• B. Dispersion
• C. Reflection
• D. Transmission

31. The diagram in the figure below shows a simple electric motor.

The coil continues to turn in the same direction because the commutator Q brushes P and R:

• A. Reverse current in the coil every half a revolution
• B. Reverse current in the coil every quarter of the revolution
• C. Reverse polarity of the field produced by the magnet
• D. Carry the coil past its vertical position every half a revolution

32. Which of the following statements isn’t true about a magnet?

• A. Magnetic poles can’t be separated
• B. A paramagnetic material is a material from which strong magnets can be made
• C. The neutral in a magnetic field is a point where there is no force experienced
• D. Heating a magnet can reduce its magnetism

33. When brass is to be copper plated, the suitable electrolyte used is:

• A. Distilled water
• B. Sulphuric acid
• C. Lead (IV) oxide
• D. Copper sulphate

34.

The diagram in the above figure shows three resistors connected in a circuit. What is the effective resistance of the current?

• A. 20.0 Ω
• B. 47.5 Ω
• C. 60.0 Ω
• D. 90.0 Ω

35. What is the most suitable fuse for an electric heater rated 2.5 kW when connected to a voltage of 240 V?

• A. 5 A
• B. 10 A
• C. 13 A
• D. 30 A

36.

A bar magnet is moved near a coil as shown in the above figure. Which of the following ways can be used to increase the size of the induced e.m.f in the coil?

1. Using a stronger magnet
2. Moving the magnet at a higher speed

(iii) Reducing the number of turns in the coil

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

37.

When the circuit in the above figure is switched on, the voltmeter:

• A. Shows no deflection
• B. Deflects in the wrong direction
• C. Reads e.m.f of the cell
• D. Reads the terminal difference across the cell

38. The transformer cores are laminated to:

• A. Reduce eddy currents
• B. Decrease the resistance of the coils
• C. Determine the energy lost by the transformer
• D. Distribute the voltage output equally within the transformer

39. In a simple cell, the source of electrons which constitute the electron current is:

• A. The zinc plate
• B. The copper plate
• C. Dilute sulphuric acid
• D. Potassium dichromate

40.

The diagram above shows a part of the gold leaf electroscope. What will happen to the leaf if a positively charged rod is brought near the cap of the electroscope? It will:

• A. Increase in deflection
• B. Remain in the same position
• C. Reduce in deflection
• D. Break off from the plate

SECTION B

1. (a) What is meant by uniformly accelerated motion?

(b)

The figure shows dots made on a ticker tape pulled by a trolley through a ticker timer. Describe the motion of the trolley if the frequency is 50 Hz.

2.

Two forces of 6 N and 10 N act at the same time on a body P of mass 500 g as shown in the above figure. Find the:

• (i) Resultant force on P
• (ii) Acceleration of P

3. (a) Explain why the sea remains cooler than land during daytime and warmer than land at night.

(b) State any one factor on which the rate of heat transfer along a metal bar depends.

4. Explain the following observations:

(a) The increase in temperature increases the pressure of the gas.

(b) In the Brownian motion experiment, smoke particles are observed to be in random motion.

5.

The above figure shows a thermos flask.

(a) Name the parts labelled A and B.

(b) State the use of part labelled A.

(c) Why do the contents of the flask ultimately get cold?

6.

The above figure shows the refraction of light rays from a distant object by a human eye.

(a) Explain whether the eye is able to see the object clearly.

(b) What is meant by accommodation?

7. (a) ^{Increasing wave-length}

The above figure shows part of the electromagnetic spectrum consisting of gamma rays, radio waves, infrared and visible light. Identify the bands to which the radiations A, B, C and D belong.

(b) State one application of the radiation in:

(i) B and A

(ii) B and B

8. (a) What is meant by the atomic number of an element?

(b) One isotope of neon is denoted by ²⁰₁₀Ne. How many neutrons does the isotope have?

(c) ⁶⁰₇₀Co is a radioactive isotope of cobalt which emits a beta particle and very high energy gamma rays to form an element X. Write a balanced equation for the nuclear reaction.

9. (a) State Ohm’s law.

(b)

Two resistors of resistances 3 Ω and 6 Ω are connected across a battery of 4 V of negligible internal resistance as shown in the above figure. Find the:

• (i) Combined resistance
• (ii) Current supplied by the battery

10. (a) What happens to an insulator when it is rubbed by another insulator of different material?

(b)

The above figure shows a conductor supported on an electrical insulator. The conductor is given some positive charge. Show how the charge is distributed on the conductor.

(c) Sketch the electric field pattern due to two unlike charges P and Q above.

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