UNEB UCE PHYSICS PAPER 1 Nov./Dec. 1989

1.   A stone is thrown vertically upwards. At the highest point , the stone

A.  has maximum velocity  

B.  is starting to move downwards with no acceleration

C.  is starting to move downwards with maximum velocity  

  D.  has zero speed

2.   The loudness of sound depends on

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

3.   Which one of the following properties of a substance doesnot change with temperature

A.   magnetism B.  electrical conductivity  

C.  density D.  mass

4.   A high voltage d.c may be obtained from a low voltage d.c by use of

A.  a dynamo   B.  an induction cell  C.  a generator  D.  a transformer

5.

The above graph shows how a boy moves between places. Between which times is the boy at rest?

A.  0 and 2   B.  2 and 4    C.  4 and 6   D.  6 and 8

6.   Which of the following is true about a transformer?

A.  the efficiency is 100%

B.  the magnitude of the e.m.f induced in the secondary doesnot depend on the e.m.f induced in the primary coil.

C.  there are no power losses as the core is well laminated

D.  passing direct current through the primary has no effect on the secondary coil.

7.  Which one of the following radiations has the listed properties

(i)  a long range in air  

(ii)  Not deflected by magnetic field  

(iii)  causes very little ionization of air molecules

A.   alpha B.   beta C.   gamma   D.   x-rays

8.  Calculate the energy supplied in one minute to a car headlamp which takes a current of 3A at 12V

A.   36J B.  240J C.  720J D.   2160J

9.  A point of maximum energy on a stationary wave is

A.   node B.  crest C.  anti-node  D.  amplitude

10.  Concrete is a mixture obtained by carefully proportioned mixture of

A.   cement, sisal , wood and water B.  sand, gravel, bamboo and water

C.  cement, sand, gravel and water D.  gravel, sand, sisal and water

11.  An electric motor is connected by cable to a 240V d.c supply. The p.d across the motor is 239V when the current flowing is 5A. The resistance of the cable s

A.  0.2Ω B.  5Ω C.  47.8Ω  D.  48Ω

12.  An air bubble of volume 30mm³ is formed at a depth of 1.0m below the surface of mercury. If the bubble rises to the surface where pressure is 760mm of mercury, calculate its volume on reaching the surface

A.  13.0mm³  B.   22.8mm³ C.  39.5mm³  D.   69.5mm³

13.   If a fixed mass of gas is kept at constant temperature its

A.  volume increases with a decrease in pressure  

B.  volume remains constant

C.  density remains the same when pressure is varied  

D.  density is inversely proportional to the pressure

14.  Which of the following diagrams shows the resultant field when a straight conductor carrying a current into the plane of the page is placed between the two poles of a magnet?

15.

A uniform metre rule of weight 2N is pivoted at the 40cm mark. Find the value of the force, P required to keep the metre rule in equilibrium if a force of 4N acts at the end of the metre rule as in the diagram above

1. 2.5N B.  5.5N C.  6N D.  6.5N

16.  Which of the following electromagnetic waves has the longest wavelength?

A.  micro-waves B.  radiowaves

C.  ultraviolet waves D.  infrared waves

17.  How many lamps marked 75W, 240V could light normally when connected in parallel having a 5A fuse.

A.  1 B.  3 C.  16 D.  26.

18.  A nuclide is denoted by the symbol ²⁰⁸₈₂Y. From this information alone, we can deduce that the nuclide

A.   is not radioactive

B.  has a total of 208 electrons

C.  has equal number of oppositely charged nucleus

D.  has more charged nucleus than uncharged nucleus

19.  For a person who is short sighted, the rays of light from

A.  distant objects are focused infront of the retina

B.  near objects are focused behind the retina

C.  distant objects are focused behind the retina

D.  near objects are focused infront of the retina

20.

The resistance wire R is connected in series with a battery and an ammeter as shown above.What will happen to the reading of the ammeter if steam is passed through the steam chest? It

A.   increases and then decreases  B.  increases and remains the same

C.  decreases and remains steady D.  remains steady

21.  A car of mass 1000 kg traveling at 48 kmh^-1is brought to rest by a constant braking force. Calculate the braking force if the car comes to rest in 15s.

A.  720N B.  1000N C.  15,000N  D.  58,000N

22.

The switch S in the figure is closed when a soft iron bar is moved inside the solenoid in the direction shown. Which of the following is likely to happen?

A.  the north pole of the compass needle will be attracted by the solenoid

B.  the north pole of the compass needle will be repelled by the solenoid

C.  the compass needle will be un affected

D.  the compass needle will rotate very fast

23.  When a girl wearing a red dress with white stripes passes under green light, her dress appears

A.   green  B.  red and green

C.  black and green D.  black and white

24.  A ball thrown vertically upwards returns to the point of projection 12s later. Calculate the speed with which the ball was thrown

A.  10ms^-1 B. 30ms^-1 C.   60ms^-1  D.  120ms^-1

25.

What is the power of the converging lense above

A. B.   C.   D.  

26.   Two cells of e.m.f 1.5V and internal resistance 1Ω are in series with a resistor of resistance 2Ω. Calculate the value of the current in the circuit

A.  1.5/4A  B.   1.5/3 A C.   3/4A D.   1A

27.  A man standing some distance from a vertical wall beats a drum. He hears the echo after 2s. Calculate the distance between the man and the wall(speed of sound in air=330ms^-1)

A.   82.5m  B.  165.0m C.  330.0m  D.  660.0m

28.  A high frequency sinusoidal wave is connected across the y plates of C.R.O without a time base. The trace on the fluorescent screen will appear like this

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29.  A stone of mass 20g falls through a distance of 10m. Calculate the kinetic energy it loses.

A.  0J B.  20J C.  200J D.  2000J

30.

The frequency of the above circular wave is 32Hz. Calculate its speed

A.  1.6ms^-1  B.  3.2ms^-1 C.  6.4ms^-1  D.  16.0ms^-1

31.  When saturated vapour is compressed

A.  more liquid evaporates B.  more vapour condenses

C.  the amount of vapour remains the same D.  the vapour becomes saturated.

32.

Three identical lamps are connected as shown above. What is the reading on the voltmeter?

A.  1.0V B.  1.5V C.  2.0V D.  3.0V

33.  How much energy is required to melt 2kg of*******( the specific latent heat of fusion of ice is 334kJ/kg)

A.  0kJ B.  167kJ C.  334Kj D.  668kJ

34.

The diagram shows the distance/time graph of a stone thrown vertically upwards. At which one of the following points P,Q,R or S is the velocity greatest?

A.  P B.  Q C.   R D.   S

35.  Saturated vapour pressure is the pressure exerted by a

A.  vapor which is in dynamic equilibrium with its liquid

B.   liquid which is in dynamic equilibrium with its vapour

C .  soild which is in dynamic equilibrium with its vapour

D.  liquid which is in dynamic equilibrium with its solid

36.  The following are some of the uses of x-rays except

A.  detection of flows in materials  B.  detection of affected tissues in living organisms

C.  destruction of cancer cells D.  preservation of cereals

37.  Which one of the following would be suitable to use in the construction of transformer-core?

A.   lead B. copper C.   soft iron  D.  aluminium

In each of the questions 38-40, one or more of the answers given may be correct. Read each question carefully and then indicate on your answer sheet according to the following

A.  if 1,2,3 only are correct B.  if only 1,3 are correct

C.  if 2,4 only are correct  D.  if 4 only iscorrect

38.  An object in unstable equilibrium continues to fall when slightly displaced because

1.  centre of gravity is lowered 2.  centre of gravity is raised

3.  potential energy is reduced 4.  potential energy is increased

39.  A car P moving with a velocity of 6ms^-1 hits a stationary car Q of twice its mass and both cars continue traveling in the same direction. If the velocity of car P reduces to 2ms^-1, which one of the following is true about the motion of the two cars after collision ?

1.  P moves with the same momentum as Q  2.  P moves with less momentum than Q

3.  P moves with less velocity than Q 4.  P moves with the same velocity as Q

40.  Total internal reflection occurs when

1.  the angle of incidence is greater than the critical angle

2.  the angle of incidence is less than the critical angle

3.  a ray of light travels from a denser to a less dense medium

4.  a ray of light travels from a less dense to a denser medium

SECTION B

1.  A non-uniform metal bar which is 4.0cm long has its centre of gravity 1.0m from the heavy end. The bar is balanced when it is pivoted from the middle and a weight of 750N is suspended form the light end.

(a)  Draw a diagram to show the forces acting on the bar

(b)  Find the weight of the bar

2.

The diagram above shows the main parts of a vacuum flask

(a)  Name parts labeled X,Y,Z

(b)  Explain how the parts labeled X,Y,Z minimize the loss of heat by a hot liquid placed in the flask.

3.

The diagram in the above shows the essential parts of a simple cell.

(a)  Name the parts labeled P,Q.

(b)  Why does the current through the cell eventually stop.

4.  A balloon filled with 50m³ of hydrogen weighs 40kg. The balloon is held in place by rope fixed to the ground. If the density of air is 1.2kgm^-3, find

(a)  the upthrust on the balloon

(b)  the force needed to hold the balloon in place.

5.  

An object placed in front of a concave mirror of focal length 15cm and its image formed 30cm behind the mirror as shown above. On the diagram draw rays to find

(a)  the object distance

(b)  the object height

6.  (a)  What is radioactivity?

(b)  The nuclide ²¹⁵₈₄Po decays to nuclide X by emission of an α-particle. Write a balanced equation for the decay.

(c)  What fraction of the original sample of radioactive substance is left after 2half-lives?

7.  (a)  State Boyle’s law.

(b)  When the pressure of 1m³of a gas at -73⁰C is increased to three times its initial value, the temperature becomes 27⁰C. Find the new volume of the gas.

8.  (a)  Sketch the variation of current with voltage for a carbon resistor

(b)

In the above figure, the resistance between A and C is 150Ω. If the resistance between A and B is 50Ω, what is the potential difference between A and B

9.  (a)  Explain why electric power is transmitted at high voltage.

(b)  An electric generator of output 2.0×10⁴W supplies power through 10 identical cables. Find the current which flows through each cable if the voltage of the generator is 5000V

10.  

A fixed mass of gas is confined in a perfectly insulated cylinder with frictionless piston. The pressure, volume and temperature of the gas are P₁,V₁ and T₁ reasoectively. The piston is then pushed inwards and held in place as shown above. P_2,V₂ and T₂ are the new pressure, volume and temperature respectively. Use the kinetic theory of matter to explain what happens to the pressure P₁ of the gas.

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