UNEB UCE PHYSICS PAPER 1 Nov./Dec. 2000

UNEB UCE 2000

Section A:

1.  In which of the following devices is kinetic energy converted to electrical energy?

A.  An accumulator. B.  An electric motor.  

C.  A combustion engine. D.  A dynamo

2.  Which one of the following relations is from the nucleus of an atom?

A.  Cathode rays B.  Gamma rays.

C.  Infra red rays. D.  Ultra violet rays.

3.  Calculate the time required for a kettle taking 10 A from a 240V supply, to heat 5 kg o water through 80o, assuming no heat loss.

A.  700 s.  B.  292 s.

C.  8.8 s. D.  1.7 s.

4.  The count rate from a radio active source is 138 counts per minute when the background rate is 10 counts per minute. If the heat half life of the source is 6 days, find the count rate after 18 days.

A.  16.0  B.  17.25

C.  26  D.  42

5.  In a write supporting a load, stress is given by

A. B.  Force x Area

C. D.      

6.   The arrangement in figure 1 is used to produce an e.m.f. What causes the e.m.f.?

A.  The attraction between the coil and magnet.

B.  The magnetic field outside the coil.  

C.  The magnet placed close to the coil.  

D.  The variation of magnetic lines linking the coil.

7.  In the atomic bomb, energy is produced by

A.  fusion.  B.  fission.

C.  radioactivity. D.  thermionic emission.

8.  An air bubble is introduced at the bottom of a jar containing mercury. Which one of the following explains what will happen to the bubble?

A.  It will be pressed by the mercury column and burst.  

B.  It will rise to the surface while decreasing in size.  

C.  It will rise to the surface while increasing in size.

D.  Nothing will happen to the bubble.

9.  Plants inside a green house emit rediations which cannot pass through the green house glass because the radiations are

A.  of short wavelength. B.  of long wavelength.  

C.  used to warm up the green house. D.  absorbed by the glass.

10.  Which of the following displacement time graphs shows a car moving away from traffic lights at a steady speed?

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11.   Which of the following statements are true about two equal forces F acting on a bar of length l, shown in figure 2?

(i)  The resultant force on the bar is zero.

(ii)  The forces cause a rotational effect.  

(iii)  The forces act in opposite directions.

(iv)  The forces produce different turning effects.

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

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

12.  The effect produced when many echoes merge into one prolonged sound is known as

A.  noise.  B.  harmonics.

C.  reverberation. D.   pitch.

13.   Figure 3 shows waves spreading out from a point. The wavelength of the waves is

A.  3cm   B.  6cm

C.  9cm     D.  12cm

14.  Which of the following only works with a direct current?

A.  Electric lamp. B.  Transformer.

C.  Electroplating. D.  Electric bell.

15.  A ticker timer is connected to the mains supply of frequency 40Hz. Find the time it takes to print three consecutive dots.

A.  0.08 s  B.  0.25 s

C.  0.050 s  D.  0.75 s

16.   Figure 4 shows a velocity-time graph for a moving body. Which one of the following statements is true about the motion of the body?

A.  Velocity of the body is constant between O and A.

B.  Velocity of the body is constant between A and B.

C.  The body is accelerating between A and B.

D.  The body is not accelerating between O and A.

17.  Which one of the following actions will cause the leaf of a negatively charged electroscope to fall?

(i)  Bringing a positively charged rod near the cap.

(ii)  Bringing a negatively charged rod near the cap.

(iii)  Connecting the can to the earth.

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

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

18.  A boxer while training noticed that a punch bag is difficult to set in motion and difficult to stop. What property accounts for this observation?

A.  Size.  B.  Inertia.  

C.  Friction. D.  Weight of the bag.

19.  Figure 5 shows a uniform metre rule of mass 0.1kg pivoted at the 80 cm mark. It balances horizontally when a mass P is hang at the 95 cm mark. Find the value of P.

A.  0.08 kg B.  0.2 kg

C.  0.4 kg  D.  1 kg

20.  A body of mass 25 kg falls freely from a height of 10 metres to the ground. Calculate its velocity as it hits the ground.

A.  4.47 ms^-1 B.  10.0 ms^-1

C.  14.14 ms^-1   D.  2500 ms^-1

21.  An object is placed between a converging lens and its principal focus. The image formed is

A.  real, magnified, upright  B.  real, magnified, inverted

C.  virtual, diminished, upright  D.  virtual, magnified, upright

22.

In figure 6, when switch K is closed, the two soft iron cores will

A.  repel each other all the time.

B.  attract each other all the time.  

C.  attract each other for just a brief moment.

D.  have no force attraction or repulsion between them

23.  A mouse of mass 0.03 kg climbs through a distance of 2 m up a wall in 4 s. the power expended in watts is

A.  0.03 x 2 x 4 x 10 B.  0.03 x 4 x 2 / 10  

C.  0.03 x 4 x 10 / 2 D.  0.03 x 2 x 10 / 4

24.  A price of material of mass 200 grams has a density of 25 kg/m³. calculate its volume in m³ .

A.  200/25  B.  200/1000 x 25

C.  1000 x 25/ 200 D.  1000 x 200/25

25.  A needle may float on a clean water but sinks when some detergent is added to water because the detergent

A.  reduces the density of water.

B.  increases adhesive force between the needle and water molecules.

C.  lowers the surface tension of water.  

D.  makes water surface slippery.

26.  The particles in a solid at room temperature are

A.  close together and vibrating.

B.  close together and stationary.  

C.  far apart and moving at random.

D.  close together and moving at random.

27.  Reinforced concrete is stronger that ordinary concrete because concrete and the steel are

A.  both brittle materials.

B.  both ductile materials.

 C.  strong in tension and compression respectively.  

D.  strong in compression and tension respectively.

28.  Which of the following are attracted towards the negative plate in an electric field?

A.  Beta particles. B.  Alpha particles.  

C.  Gamma rays. D.  Neutron.

29.  What occurs when a body is made to vibrate with its natural frequency due to external vibration?

A.  Echo. B.   Resonance.

C.  Refraction. D.  Reverberation.

30.  A man standing 85 m from a tall wall fires a gun and hears the echo from the wall after 0.5 s. calculate the speed of sound in air.

A.  340ms^-1 B.  170 ms^-1  

C.  85 ms^-1  D.   43 ms^-1

31.  For safety in house, a fuse and a switch are connected to

32.  Which of the following are secondary colours only?

A.  Red, green and yellow.  B.  Blue, yellow and magenta.  

C.  Yellow, cyan and magenta.  D.  Red, green and blue.

33.  When a pressure of a fixed mass of a gas is reduced by half, its volume

A.  doubles at constant temperature.

B.  is halved at constant temperature.  

C.  is halved if the temperature is also halved.

D.  remains the same at constant temperature.

34.  A man 1.75 m tall stands at a distance of 7.0 m from the pinhole of pinhole camera. If the film is 0.20 m behind the pinhole, find the length of the image of the man formed on then film.

A.  8.75 m  B.  4.00 m

C.  0.80 m  D.   0.05 m

35.  When polythene and wool are rubbed against each other and then separated, they acquire

A.  no charge.

B.  equal amount of same type of charge.  

C.  equal and opposite charges.  

D.  both acquire positive and negative charges.

(00.A.Q:36.  Which of the following shows a piece of material in a magnetized condition?

(00.A.Q:37.  In figure7, the ammeter A reads 4A and the voltmeter V reads 4V. find the value of R.

A.  1Ω B.  2Ω  

C.  3Ω D.  4Ω

(00.A.Q:38.  When a kg of certain liquid is heated for 10 s its temperature rises by 25^oC. if the power supplied is 1000watts, find the specific heat capacity of the liquid.

A.  40 J kg^-1 K^-1  B.  400 J kg^-1 K^-1  

C.  1000 J kg^-1 K^-1  D.  2500 J kg^-1 K^-1

(00.A.Q:39.  A rectifier is used to

A.  step up an a.c voltage.

B.  amplify an a.c current.  

C.  change an a.c voltage to a.d.c voltage.  

D.  change a.d.c. voltage to an a.c. voltage.

(00.A.Q:40.  An electric appliance having 4 heating elements, each rated at 0.75kW, is used on a 240 V mains. What is the power rating of the appliance?

A.  80 kW. B.  60 kW.  

C.  3 kW. D.  3W.

SECTION B

(00.B.Q:1.  (a)  What is uniform velocity?  

(b)  A car traveling at 20 ms^-1 is accelerated for 10 s at 2 ms^-2. calculate the total distance covered during this time.

(00.B.Q:2.  (a)  State the principle of moments.  

(b)  A uniform beam of weight 2.5 N is pivoted at its mid-point P, as shown in figure 8. the beam remains in equilibrium when force R and S act on it. If R is 5N, find the:

(i)  value of S.  

(ii)  reaction at the pivot.

(00.B.Q:3.  (a)  Why is a petrol engine referred to as a four-stroke engine?  

(b)  State two reasons why the efficiency of a petrol engine is quite low.

(00.B.Q:4.  (a)  What is meant by specific heat capacity of a substance?  

(b)  When a block of iron of mass 2 kg absorbs 19 kJ of heat, its temperature rises by 10^oC. Find the specific heat capacity of the iron.

(00.B.Q:5.  The diagram in figure 9 shows an arrangement for observing Brownian motion.

(a)  Explain:

(i)  the observation made.  

(ii)  what will be observed when the glass cell temperature is raised.

(b)  State one factor which determines the rate of diffusion of a gas.

(00.B.Q:6.  (a)  What is meant by thermiomic emission?  

(b)  State two differences between cathode rays and x-rays.  

(c)  In the production of x-rays tube, why must be target be cooled?

(00.B.Q:7.  (a)  What is a transverse wave?  

(b)  The diagram in figure 10 represents a wave traveling in water.

(i)  Name the part labelled B  

(ii)  If the distance represented by a is 20cm and the speed of the wave is 8.0 ms ^-1, what is the frequency of the wave?

(00.B.Q:8.  (a)  Define focal length of a converging lens.  

(b)  The focal length of a converging 10.0 cm. What is its power?  

(c)  State any two properties of an image of a real object formed in a diverging lens.

(00.B.Q:9.  A source of e.m.f. 20V and negligible internal resistance is connected to resistors of 2Ω, 2Ω and 3Ω as shown in figure 11.

Find the ammeter reading when switch K is

(i)  open  

(ii)  closed

(00.B.Q:10.  (a)  State any two factors which determines the magnitude the e.m.f. induced in a

coil rotating in a magnetic field.  

(b)  Explain why soft iron is preferred to steel in making electromagnets.

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