UNEB UCE PHYSICS PAPER 1 Oct./Nov. 1988

SECTION A

1.   Which of the following substances is not elastic?

A.  Glass B.  Rubber C.  Plastic D.  Copper

2.  A bus carrying a heavy load on its rack is more unstable when moving because

A.  its centre of gravity is raised B.  the friction on the ground increases

C.  its total weight is increased D.  the pressure on the tyres is increased

3.   Which one of the following will affect the number of electrons emitted in a thermionic tube?

 (i)  the p.d between anode and cathode (ii)  the pressure of the filament

(iii)   the current flowing in the filament circuit

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

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

4.   Which one of the following graphs will affect the number of motion of a body moving with uniform velocity

*********

5.

A block of mass 1kg is supported by a force F on a trough plane inclined to the horizontal at 30⁰. If the static frictional force is 5N, find the value of F.

A.  25N B.  8.7N C.  5.0N D.  0.0N

6.  The sensitivity of a thermometer can be increased by

A.  increasing the volume of the bulb

B.  increasing the amount of liquid in the thermometer

C.  decreasing the thickness of the stem wall

D.  decreasing the diameter of the bore of the capillary tube

7.   When a body in stable equilibrium is tilted slightly

A.   the position of its centre of gravity is lowered

B.  the position of its centre of gravity is raised

C.  the position of its centre of gravity doesn’t change

D.  it topples over

8.   A fly wheel connected to an internal combustion engine is made heavy in order to

A.   store rotational kinetic energy B.  store kinetic energy C.   produce a spark  D.  helps valves to open at regular intervals

9.   A bullet of mass 150g is fired with a speed of 400ms^-1. The rifle recoils with a speed of 10ms^-1. Find the mass of the rifle

A.   60.0kg B. 6.0kg C.  3.0kg D.  0.6kg

10.  Which one of the following equations does not represent the expression for power P, in terms of voltage, V, current I and resistance R

A.  P=VI B.  P=I²R   C.  P=V²/R D.  P=R²/I

11.  A parachute released from an aeroplane will fall with constant velocity when

A.  its weight is equal to the up thrust

B.  its weight is equal to the air resistance

C.  air resistance is equal to the up thrust  

D.  the upthrust plus the air resistance are equal to its weight

12.   In metals heat is transmitted by

A.   conduction and radiation  B.  convection and radiation

C.  conduction only D.  convection only

13.   Calculate the pressure exerted on the road by a car of mass 740 kg if the area of contact between the road and each of the four tyres is 50cm³

A.   37Nm^-2  B.  37×10⁴Nm^-2  C.   3.7×10⁵Nm^-2 D.  1.48×10⁶Nm^-2

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

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

15.   A stone is thrown horizontally form a high tower, which of the following explains its motion

 (i)   vertical acceleration is constant (ii)  vertical acceleration is increasing

(iii)  horizontal velocity is constant

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

16.   A mass of a radioactive substance falls to ¼ of its original mass after 10days. What is its half life?

A.  2.5days  B.   5 days  C. 20 days  D. 40 days

17.

The above figure shows a charged conductor with the points W,X,Y being on the outside and Z on the inside surface. Arrange W,X,Y and Z in order of increasing concentration of charge

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

18.  Which of the following is not true about a vacuum flask?

A.  it controls heat loss by radiation using the vacuum

B.  it can be used to keep cold liquids cold

C.  the cork is used to reduce loss of heat by convection

 D.  the silvering of the walls on the vacuum side reduces loss or gain of heat by radiation

19.

The above diagram shows two beakers X and Y being heated in a water bath at 100⁰C. Beaker X contains cold water only whereas beaker Y contains ice and water. Which of the following statements is not true?

A.   the water in X will show a steady rise in temperature until it boils

B.   the temperature of Y will remain constant until all the ice has melted

C.  the temperature of Y will remain constant until the contents boil

D.  the temperature of X will remain constant when the contents start boiling

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

  (i)  P moves with the same momentum as Q  

(ii)  P moves with less momentum than Q

(iii)  P moves with the same velocity as Q

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

21.

The graph above shows extensions of a wire against load added to the wire. Hooke’s law is obeyed between

1. OY     B.  AN C.  AB D.   OA

22.   Which of the following is the correct order of energy changes at the hydro electric power station?

A.  kinetic energy potential energy electrical energy

B.  potential energy kinetic energy electrical energy

C.  potential energy heat energy electrical energy

D.  heat energy potential energy electrical energy

23.

.

A block of wood of mass 4kg is placed on a smooth table and two forces applied on it as shown in the above figure. If the acceleration of the body is 2ms^-2, in the direction of 10N force, find F

A.  2N B.  2.5N C.  6N D.  30N

24.

An electron beam is incident into the page at right angles to the magnetic field formed between two magnets R and S as shown in the above diagram. The beam will be deflected

A.  downwards  B.  towards magnet R  C.   towards magnet S  D.   upwards

25.   A man standing some distance from a vertical wall beats a drum. He hears the echo after 2s. If the speed of sound air is 330ms^-1, calculate the distance between the man and the wall.

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

26.   A car moves from a point X to Y at a constant velocity. It remains stationary for sometime and then returns to X at a constant velocity. Which of the following graphs describes the motion

******

27.   Which one of the following controls the brightness of a spot on the screen of a cathode ray oscilloscope

A.  X plates  B.  Y plates C.  the grid D.   the anode

28  A beam of white light is to be passed through a combination of two filters. Which filter combination will allow only red light

A.  blue and red filters B.   cyan and red filters  

C.  yellow and magneta filters  D. cyan and magneta filters

29.

The above figure shows a plank of wood across a river. When there is no weight on it,

A.  X is under tension and Y is under compression  

B.  X is under compression and Y under tension

D.  both X and Y are under tension

D.   both X and Y are under compression

30.  Which one of the following statements is true about a transformer

A.  the efficiency is100%

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

C.  the magnitude of the .em.f induced in the secondary coil doesn’t depend on the e.m.f in the primary coil

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

31.  An iron ball coated black is put in the sun for some time. What will happen when the ball is taken into a *******

A.  air will circulate around the ball and maintain the temperature of the immediate surroundings at a higher value

B.  the ball will absorb heat from the surroundings to maintain its high temperature

C.  the temperature of the immediate sorrondings of the ball will drop

D.  the ball will radiate heat to the immediate surrounding air.

32.   Which one of the following pairs gives a defect and its correction in a simple cell

33.

The ammeter in the above diagram indicates the current through

A.  lamp P only B.   lamps P and Q  

C.  lamps Q,R and S D. lamps P,Q,R and S

34.

The figure above shows a light, smooth pulley used to lift a load of 16N with an effort E. the mechanical advantage of the system is

A.  128 B.  2 C.  1 D.  ¹/₂

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

A.   0.2Ω B.  5Ω C.  47.8Ω D.  48Ω

36.  When a liquid is heated

A.  its molecules moe with the same speed  

B.  its density decreases

C.  evaporation takes place throughout the liquid  

D.  boiling occurs at low temperatures

37.   How much energy is required to melt 2kg of ice at 0⁰C?

A.  0 kJ B.  167 kJ C.334 kJ D. 668 kJ

38.

A galvanometer G is connected in the circuit as shown in the above figure . The galvanometer is intended to measure

A.  the p.d across R  B.   the power dissipated by R

C.   the resistance of R  D.  the current through R

39.  In a four-stroke internal combustion engine, the work required for initial induction and compression comes from

A.   the rotational kinetic energy stored in the fly wheel  

B.   the movement of the steering wheel

C.  the separate starter motor

D.  the sparking plug

40.

The waveform obtained when Y and X are connected to a cathode ray oscilloscope is

SECTION B

1.

The above velocity –time graph represents the motion of a small sphere dropped centrally down a tall column of a liquid.

(a)  Name forces which act on the sphere and state their directions

(b)  What happens to the sphere between A and B

2.   (a)  The diagram below shows two identical bar magnets placed close to each other. Sketch the

resultant magnetic field pattern

(b)  Name three ways of demagnetizing a bar magnet

3.   (a)   What is meant by refractive index of a medium?

(b)  A ray of light is incident on the water-glass boundary at an angle of 41⁰. Calculate the angle of refraction ,r, if the refractive indicies of water and glass are 1.33 and 1.50 respectively

4.   An object is placed perpendicular to the principal axis between the principal focus and the centre of curvature of a concave mirror. Sketch a ray diagram to show the formation of an image of the object

**********

5.   (a)

The diagram above shows a hot cathode X-ray tube

(i)   Name the parts labeled D,E,G and H

(ii)  What is the purpose of the high voltage

(b)  State two applications of X-rays

6.

The diagram above shows a trolley of mass 50kg connected to a mass of 10kg by a light string which passes over a smooth pulley. The trolley moves over a smooth horizontal surface

(a)  What is the horizontal force acting on the trolley

(b)  What is the total mass in motion

(c)  Find the acceleration of the trolley

7.

The diagram above shows the variation of the stress against strain for a ductile material

(a)  What is meant by the terms stress and strain

(b)  What is the significance of points P and Y

8.  A galvanometer of full scale deflection 15mA is converted into an ammeter of full scale deflection 3.0A by connecting a low resistance shunt in parallel with the galvanometer

(a)  What will be the maximum current through the shunt?

(b)  Find the resistance of the shunt if internal resistance of the galvanometer is 5Ω

9.   The nucleus of a radioactive isotope ⁶⁰₂₇Co decays to Ni with emission of β and γ radiation

(a)  Write down a balanced equation for the decay process

(b)   What does the figure 60 stand for?

10.  (a)  State one difference between boiling and evaporation of liquids

(b)  Explain each of the following observations

(i)  There is no change in temperature at boiling point even though heat is being supplied

(ii)   A change in pressure alters the boiling point of a liquid

**********