UNEB UCE PHYSICS PAPER 1 Nov./Dec. 1992

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PAPER 1(1992)

SECTION A

1.  Which of the following changes occurs when a ripple from a region of deep water reaches a region of shallow water?

A.  the velocity remains constant and the wave-length increases

B.  the velocity decreases and the wavelength decreases

C.   the frequency increases and the velocity increases

D.   the frequency decreases and the wavelength increases

2.   In a house wiring system, all connections to power points are in parallel so as to

A.  supply the same current

B.   operate the same voltage

C.  minimise the cost of electricity

D.  consume the same amount of energy

3.

In the above diagram, boy X clapped his hands once and boy Y heard two claps, the interval between their arrival being 1s. Calculate the distance between X and Y (speed of sound=330ms^-1)

A.  255m B.  330m C.  345m D.  510m

4.   How much heat is required to raise the temperature of 20g of water from 30⁰C to 60⁰C?

A.   2520J B.   6300J C.  8400J D.  126000J

5.

In the above diagram, S is the source of A, B and Y rays. The beams at X and Y will contain

 X Y

1. α,β,γ β,γ only
2. β,γ only γ only
3. β,γ only β,γ only
4. α,γ only γ only

6.  Air in a 3litre vessel at 27⁰C exerts a pressure of 2Nm^-2. Calculate the pressure that the same mass of air would exert if it was contained in a 2litre vessel at -33⁰C

A.  1.1Nm^-2 B.  20Nm^-2 C.  2.4Nm^-2   D.  3.7Nm^-2

7.   ²³⁴₉₀X ²³⁴₉₁Y+P in the above reaction, P is likely to be

A.  an alpha particle B.  a beta particle

C.   A gamma ray  D.  A neutron

8.

What is the reading of voltmeter V in the circuit in the above figure?

A.  2.0V B.   4.0V C.  5.0V D.  10.0V

9.  A current of 5 A flows through a given point in a circuit of 2 minutes. Calculate the quantity of charge that passes the point

A.   2.5 C B.   10 C C.  300 C D.  600 C

10.  A man of mass 50 kg climbs 40 steps up stairs. If each step is 0.2mhigh the potential energy gained is

A.   100Ј B.  400Ј C.  4000Ј D.  20,000Ј

11.

The diagram above shows part of a combustion engine. What is the likely stroke in the bicycle?

A.   Inlet stroke  B.  Power stroke

C.   Exhaust stroke D.  Compression stroke

12.  If a load 1N extends a spring by 5cm. What extension will a load of 0.6N produce?

A.  1.2cm B.  3.0cm C.  8.3cm D.  30.0cm

13.

The diagram above shows a bar magnet which has picked up an iron nail. Plotting compasses P and R are placed as shown in the diagram. Which direction will R point to?

A. B C   D

14.   The colour seen in a tin soap film is due to?

A.  refraction  B.  Interference  C.  Diffraction  D.  total internal reflection

15.

In the circuit above the readings of the ammeter, A and voltmeter V, when switch S is opened and closed respectively are as shown in the table below

The internal resistance of cell E is

A.  0.0Ω B.  0.5Ώ  

C.  1.0Ω D.  1.5Ω

16.  The refractive index of glass is 1.5 calculate the angle of refraction for the light incident on glass at an angle of 30⁰

A.  19.5⁰ B.  42.0⁰ C.  45.0⁰ D.  48.6⁰

17.

The amplitude of the wave in the above figure is

A.  6cm B.  8cm C.  12cm D.  16 cm

18.   The mass of a radioactive substance falls to ¼ of its original mass after 10 days. What is its half-life?

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

19.  Which of the following sets contains only good conductors of heat?

A.   copper, wood, air, B.  Silver, gold, rubber

C.   iron, mercury, copper D.  Magnesium, paper, wool

20.  A car of mass 500kg starts from rest and gains a speed of 80ms^-1 in 5s. Calculate the force applied on the car.

A.  16N B.  5000N C.  8000N D.   80000N

21.  An electroscope is negatively charged by induction. This means that it has

A.  gained electrons B.  gained protons  

C.   lost electrons D.   lost protons

22.  Tungsten is used as the anode in the x-ray tube because

A.   it conducts electricity easily B.  Produces x-rays easily

C.  does not melt easily D.   it is easily available

23.  A body of mass 20kg falls freely from a height of 5m. Find the velocity with which it hits the ground

A.  3.2ms^-1  B.  4.5m^-1 C.   7.1ms^-1 D.  10ms^-1

24.  Which of the following sets contains only vector quantities?

A.  weight, displacement, acceleration, magnetic field

B.  energy, electric field, momentum, distance

C.   mass, negatively, force, speed

 D.  specific heat capacity, power, time, volume

25.  A stone thrown vertically upwards returns to the ground after sometime. Which of the following graphs describes its motion?

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26.  At room temperature, air is less dense than water because air molecules

A.  move faster B.  are smaller

C.  have greater force of attraction  D.  are more widely separated from each other

27.  Two solid tubes have the same mass, but their surface areas are in the ratio 16:1. What is the ratio of their densities?

A.   64:1 B.  1:64 C.   4:1 D.  1:4

28.  The production of electrical energy in a nuclear reactor follows a sequence

A.  nuclear energy –chemical energy –kinetic energy-electrical energy

B.   nuclear energy –heat- chemical energy – electrical energy

C.  nuclear energy – heat- kinetic energy – electrical energy

D.   nuclear energy – kinetic energy – heat- electrical energy

29.  The main function of a step-up transformer is to

A.  change a.c to d.c  B.  change d.c to a.c  

C.  increase the current  D.  increase voltage

30.  10⁶kg of water falls from a height of 50m every second. Calculate the power generated

A.  2.0×10⁴W B. 2.0×10⁵W C.  5.0×10⁷W D.  5.0×10⁸W

31.  An oil drop of volume 1×10^-9m³ spreads on a water surface to form a patch of area 5×10^-2m². If the patch is one molecule thick, find the approximate number of molecules in the drop

A.  1×10⁹ B.  2×10⁸ C.  3×10¹⁴ D.  5×10⁷

32.  Sound travels faster on a hot day than on a cold day because

A.  the speed of air molecules is higher on a hot day than a cold day

B.  there are more convectional currents on a hot day than on a cold day

C.  there are less air molecules on a cold day than on a hot day

D.  there are more air molecules on a cold day than on a hot day

33.  A rectangular block of mass 48kg measures 4mx3mx2m. What is the least pressure it can exert on a given surface?

A.  20Nm^-2 B.   40Nm²   C.  60Nm² D.  80Nm^-2

34.  Two forces of 5N and 12N act at a point at right angles to each other. Find the magnitude of the resultant force

A.   7N B.  13N C.  17N D.   60N

In each of the questions 35–40, 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 is correct

35.  The advantage(s) of alternating current over direct current in mains supply is/are

1.  Less power is lost in the transmission of a.c  

2.  It is less dangerous to handle at the same voltage value

3.  It is easier to step up or down

 4.  It is easier to generate

36.  Concrete is weak in tension because

1.  It is not fired so it becomes weak when it dries

2.  The composition of concrete is not strong to resist tension

3.  It cannot be moulded into shapes suitable to resist tension

4.  When it dries, numerous cracks are formed

37.  The frictional force between two solids surfaces in contact

1.  Is a maximum just before motion takes place

2.  Increases as the weight of the solid on top increases

3.  is independent of the speed of the surfaces

4.  Increases when the area of contact is increased

38.  Two particles of each mass m, travel in opposite directions along the same path towards each other with a velocity v. Which of the following statement(s) is/are true about the motion of the particles?

1.  Each particle has a momentum of mv.  

2.  Each particle has a kinetic energy of mv²

3.  The total momentum of two particles is 0

4.  The kinetic energy of each particle will increase on collision

39.  The advantage(s) of mercury over alcohol as a thermometric liquid is/are

1.  Mercury is opaque  2.  Mercury does not wet glass

3.   Mercury is a good conductor of heat  4.  Mercury expands more than alcohol

40.

The diagram in the above figure shows a pattern of iron fillings between two magnetic poles P and Q. Which of the following statement(s) is/are true?

1.  The force of repulsion between P and Q is weakest at X

2.  P and Q are like poles

3.  Poles P and Q are attracting

4.  X is a neutral point

SECTION B(1992)

1.  (a)  What is meant by rectilinear propagation of light?

(b)  An opaque object is placed in front of a source of light. Draw ray diagrams to show the formation of shadows when part

(i)  A point source is used

(ii)  an extended source is used

2.  (a)  Explain how a rifle jerks backwards when a bullet is fired

(b)  A bullet of mass 1.5×10^-2kg is fired from a rifle of mass 3kg with a muzzle velocity of 100kmh^-1. Calculate the recoil velocity of the rifle.

3.  (a)

The above diagram shows a structure fixed on a wall so that it stands in the vertical plane and supports a load as indicated. Identify one strut and one tie from the structure

(b)

The above figure shows a diagram of a roof structure. Show on the diagram one way of strengthening the structure by using two additional girders

4.   (a)  What is meant by

(i)  Plane progressive wave

(ii)  stationary wave

(b)

A convex obstacle, L, is place perpendicularly to the axis of a slit AB as shown in the above figure. Sketch the wave pattern obtained when plane waves are incident onto the slit

5.  (a)  Define moment of a force

(b)  A uniform metre rule is balanced at the 30cm mark when a load of 0.80N is hung at the 0 mark. Find the mass of the metre rule

6.  An electrical appliance is rated 240V 60W

(a)  What do you understand by this statement

(b)  Calculate the current flowing through and the resistance of the appliance when the appliance is operated at the rated values

7.  Two identical capillary tubes are placed upright, one in a beaker of mercury and the other in a beaker of water

(a)  Draw diagram to show the liquid levels inside and outside the capillary tubes

(b)  Explain the observations in (a) in terms of forces between molecules

8.

The above diagram shows the current circuit of a thermionic diode

(a)  Name the parts labeled A and B

(b)  Why is the thermionic diode highly evacuated

(c)  Des briefly the action of a thermionic diode

9.  *******

The velocity-time graph above shows the motion of 2kg mass. Calculate

(a)  The acceleration of the mass

(b)  The force acting on the mass

(c)  The total work done by the end of 8s

10.

An aluminium foil carrying a current is placed in a magnetic field as shown above.

(a)  When switch K is closed momentarily. A force acts on the foil. State

(i)  The direction of the force

(ii)  two factors which affect the magnitude of the force

(iii)  what happens to the force when the foil is slowly turned until its ends point exactly in N-S direction of the magnetic field

(b)  Name one device which works on the principle illustrated in the above diagram

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