WAEC - Physics (1991)

1
Which of the following is a fundamental quantity?
إجابة
(C)
lenght
2
A body moves with a constant speed but has an acceleration. this process if it
إجابة
(B)
moves in a circle
3
A ball is projected horizontally from the top of a hill with a velocity of 20m^-1. If it reaches the ground 4 seconds later, what is the height of the hill? (g = 10ms^-2)
إجابة
(C)
80m
4
A body moving with uniform acceleration has two points(5, 15) and (20, 60) on the velocity-times graph of its motion. Calculate
إجابة
(B)
3.00ms^-2
5
the diagram above shows the position of a simple pendulum set in motion. At which of the positions does the pendulum have maximum kinetic energy?
إجابة
(C)
3
6
An orange fruit drops to the ground from the top of a tree 45m tall. How long does it takes to reach the ground? (g = 10ms^-2)
إجابة
(A)
3.0s
7
power is defined as the
إجابة
(E)
energy expended per unit time
8
The product PV where P is pressure and V is volume has the same unit as
إجابة
(B)
work
9
The diagram represents a block-and-tackle pulley system on which an effort of 50N is just able to lift a load of weight W. If the efficiency of the machine is 40%. find the value of W
إجابة
(D)
120N
10
A boatman facing north wants to cross a flowing river to a point directly opposite its position at the other bank. If the river is flowing eastwards, in what direction should he row his boat?
إجابة
(C)
north-west
11
The diagram above represents six maximum and minimum thermometer. If the temperature of the surrounding falls, which of the following correctly states how the thermometer would respond to the change in temperature?
إجابة
(B)
S₁ would not move but S₂ would move upwards
12
A wire, 20m long is heated from a temperature of 5oC to 55oC. If the change in length is 0.020m, calculate the linear expansivity of the wire
إجابة
(C)
2.0 x 10^-5k^-1
13
A water fall is 420m high. Calculate the difference in temperature of the water between the top and bottom of the water fall. Neglect heat loses(g = 10.0m-2 specific heat capacity of water = 4.20 x 10\(^3\) JKg-1 K-1)
إجابة
(B)
1.0^oC
14
The set-up illustrated above shows a capillary tube of uniform cross-sectional area in two different arrangements. Using the data in the diagrams. Calculate the pressure of the atmosphere
إجابة
(B)
75cm of Hg
15
A fixed mass of gas of volume 600cm³ at a temperature of 27^oC is cooled at constant pressure to a temperature of 0^oC. What is the change in volume?
إجابة
(A)
54cm²
16
The boiling point of a liquid depends on the following except the
إجابة
(C)
volume of the liquid
17
A team trap is a component of the apparatus used in determining the specific latent heat of vaporisation of steam. In the steady steady state, the steam trap
إجابة
(C)
ensures that only dry steam gets into the calorimeter
18
a tap supplies water at 26^oC while another supplies water at 82^oC. If a man wishes to bathe with water at 40^oC the ratio of hot mass of hot water to that of cold water required is
إجابة
(A)
1:3
19
Melting ice cools an orange drink far better than the same mass of ice-cold water because
إجابة
(D)
ice absorbs latent heat during melting
20
The saturation vapour of a liquid depends on its
إجابة
(B)
temperature
21
Two forces, whose resultant is 100N are perpendicular to each other. If one of them makes an angle of 60^o with the resultant, calculate the magnitude. (Sin 60^o = 0.8660, Cos 60^o = 0.500)
إجابة
(E)
50.0N
22
The graph above shows the expansion of water as the temperature increases from 0^oC. Which of the following deductions from the graph are true? i. Water has its maximum density at Q. ii. The volume of water is greater at 0^oC than at 4^oC. iii. The volume of water decreases uniformly when cooled from 100^oC. iv. When water solidifies, its volume increases
إجابة
(E)
i, ii and iv only
23
Two mirrors are inclined as shown in the diagram. A ray of light RO strikes the arrangement at O and emerges along PO. The emergent ray has been deviated through
إجابة
(B)
180^o
24
In the arrangement illustrated above, Y and B are yellow and blue transparent light filters respectively through the filters is
إجابة
(E)
black
25
A ray of light is incident at an angle of 30^o on a glass prism of refractive index 1.5. Calculate the angle through which the ray is minimally deviated in the prism. (The medium surrounding the prism is air)
إجابة
(A)
10.5^o
26
Calculate the refractive index of the material of the glass block shown in the diagram if YZ = 4cm
إجابة
(D)
1.67
27
An image which can be formed on a screen is said to be
إجابة
(E)
real
28
Which of the following are true of plane-polarised light? i. Plane polarisation of light is the formation of hydrogen bubbles on the particle of light. ii. Plane polarisation of light is the splitting of light into its spectral components iii. A plane polarised light vibrates in one plane. iv. Polarisation of light is characteristic of transverse vibration
إجابة
(D)
iii and iv only
29
At which of the following distances from the lens should a slide be placed on a slide projector if f is the focal length of the projector length?
إجابة
(C)
equal to f
30
what part of the camera corresponds to the iris of the eye?
إجابة
(D)
diaphram
31
Which of the following is not a mechanical wave?
إجابة
(C)
radio waves
32
Which of the following remains unchanged as light travels from one medium to the other? i. speed. ii. wavelength. iii. frequency.
إجابة
(C)
iii only
33
Which of the following statements about wave is not correct? i. A wavefront is a line which contains all particles whose vibration are in phase. ii. The direction of propagation of a wave is the link drawn parallel to the wavefront. iii. A wavefront is a circle which is common to particles that are in the same state of disturbance
إجابة
(E)
ii and iii only
34
What type of motion does the skin of a talking drum perform when its being struck with the drum stick?
إجابة
(C)
vibratory
35
The sound from a bell in an enclosed jar gradually faints away while the jar is being evacuated. Which of the following explains this observation?
إجابة
(D)
There is no more material medium
36
Which of the following statements is true of the diagram shown above?
إجابة
(A)
the two point, A and B are in phase
37
A man standing 300m away from the wall sounds a whistle. The echo from the wall reaches him 1.8sec. later, calculate the velocity of sound in air
إجابة
(B)
333.3ms^-1
38
In which of the following is a stationary wave produced? i. A vibrating turning fork held near the end of a resonance tube closed at one end. ii. A string tightly stretched between two points and plucked at its middle. iii. The tuning fork vibrating in air
إجابة
(C)
i and ii only
39
A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field b in the direction of the field. The force on the particle is
إجابة
(D)
O
40
If the frequency of the e.m.f. source in the a.c. circuit illustrated above is \(\frac{500}{\pi}\)Hz. What is the reactance of the inductor?
إجابة
(C)
900
41
Two objects of masses 80kg and 50kg are separated by a distance of 0.2m. If the gravitational constant is 6.6 x 10^-11Nm kg, calculate the gravitational attraction between them.
إجابة
(D)
6.6 x 10^-6N
42
Two capacitors C₁ and C₂ are connected as shown in the diagram. The capacitance C₂ is twice C₁ when the key is opened the energy stored up in C₁ is W. If the key is later closed and the system is allowed to attain electrical equilibrium, the total energy stored in the system will be
إجابة
(E)
3W
43
In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most?
إجابة
(E)
E
44
Which of the following is stored by dry Leclanche cell?
إجابة
(A)
chemical energy
45
Using the data in the circuit illustrated above, calculate the value of R
إجابة
(E)
50.00\(\Omega\)
46
A 90W immersion heater is used to supply energy for 5 minutes. The energy supplied is used to completely melt 160g of a solid at its melting point. Calculate the specific latent heat of the solid.
إجابة
(D)
168.75Jg^-1
47

In the circuit above R is a resistor whose resistance increases with an increase in temperature. L1 and L2 are identical lamps. If the temperature of R increases
إجابة
(E)
L₁ and L₂ becomes brighter
48
A house is supplied with a 240V a.c mains. To operate a door bell rated at 8v, a transformer is used if the number of turns in the primary coil of the transformer is 900. calculate the number of turns in the secondary coil of the transformer
إجابة
(A)
30
49
The diagram above shows a current carrying wire between the poles of a magnet. In which direction would the wire tend to move?
إجابة
(B)
out of the paper
50
An induction coil is generally used to?
إجابة
(E)
produce a large output voltage
51
The unit of stress is
إجابة
(C)
Nm^-2
52
Which of the following statements above viscosity are correct? when a ball falls through a viscous liquid i. viscosity opposes the gravitational force on the ball. ii. viscosity opposes the upthrust on the ball. iii. viscosity is in the same direction as the upthrust on the ball. iv. as the ball falls faster the more viscous the liquid is
إجابة
(A)
i and iii only
53
Which of the following statements is not correct? Isotopes of an element have
إجابة
(D)
different proton numbers
54
plane as 63cm of HG while a ground observer records a reading of 75cm of Hg with his barometer. assuming that the density of air is constant, calculate the height of the plane above the ground. (Take the relative densities of air and mecury as 0.00136 and 13.6 respectively
إجابة
(E)
120,000m
55
When a metal surface is irradiated, photoelectrons may be ejected from the metal. The kinetic energy of the ejected electrons depends on the
إجابة
(E)
frequency of the radiation