WAEC - Physics (2001)

1
Which of the following physical processes cannot be explained by the molecular theory of matter?
Răspuns
(C)
radiation of heat
2
A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms^-2, determine the reading on the spring balance. [g = 10ms^-2]
Răspuns
(B)
12.5N
3
An object weight 10N immersed in a liquid displaces a quantity of the liquid. If the liquid displaced weighs 6N, determine the upthrust of the object
Răspuns
(C)
6N
4
Which of the following statements about pressure is not correct? pressure
Răspuns
(A)
increases with an increase in surface area
5
The apparent weight of a body fully immersed in water is 32N and its weight in air is 96N. Calculate the volume of the body. [Density of water = 1000kgm^-3, g = 10ms^-2]
Răspuns
(B)
6.4 x 10^-3m³
6
A block weighing 15N rests on a flat surface and a horizontal force of 3N is exerted on it. Determine the friction force on the block
Răspuns
(C)
3.0N
7
Which of the following equations represents the distance x, travelled by a body moving on a straight road with a constant speed? [The other symbol have their usual meanings]
Răspuns
(B)
x = Ut
8
The amplitude of the motion of a body performing simple harmonic motion decreases with time because
Răspuns
(A)
friction force dissipate the energy of motion
9
The amplitude of a particle executing simple harmonic motion in 5cm while its angular frequency is 10 rad s^-1. calculate the magnitude of the maximum acceleration of the particle
Răspuns
(D)
5.00ms^-2
10
The time rate of change of momentum is
Răspuns
(B)
force
11
Which of the following statements about elastic collision is correct?
Răspuns
(C)
both kinetic energy and momentum are conserved
12
Electrical resistance is a property of an electrical energy to be converted into
Răspuns
(B)
heat energy
13
A simple machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is applied to it. Calculate the velocity ratio of the machine
Răspuns
(B)
13.3
14
A screw jack with a Tommy bar of length 12cm is used to raise a car through a vertical height of 25cm by turning the Tommy bar through 50 revolutions. Calculate the approximate velocity ratio of the jack [\(\pi = 3.142\)]
Răspuns
(D)
151
15
a beam PQ pivoted at P carries a load of 80N as shown above. Calculate the effort E, required to keep it horizontal. [neglect the weight of the beam]
Răspuns
(D)
13.3N
16
A resistance thermometer has a resistance of 20\(\Omega\) at 0^oC and 85\(\Omega\) at 100^oC. If its resistance is 52\(\Omega\)in a medium, calculate the corresponding temperature
Răspuns
(A)
49.2^oC
17
A given mass of an ideal gas has a pressure of 500Nm-2 at -13ºC. If its volume remains constant. Calculate its pressure at 247ºC.
Răspuns
(D)
1000Nm^-2
18
The volume of an ideal gas at a pressure of 77cmHg and temperature 60^oC is 24cm³. If the temperature and pressure are increased to 98^oC
and 81cmhg respectively, calculate the new volume of the gas
Răspuns
(C)
254.2cm³
19
The amount of heat given out or absorbed when a substance changes its state at a constant temperature is known as
Răspuns
(A)
latent heat
20
Which of the following physical qualities affects the saturated vapour pressure of a liquid ?
Răspuns
(A)
temperature
21
Humidity is used to describe the amount of
Răspuns
(D)
water vapour in the amosphere
22
Surface waves travelling in deep water at 15ms^-1 are incident at a shallow water boundary. If the angles of incidence and refraction are 45^o and 30^o respectively. Calculate the speed of the waves in shallow water
Răspuns
(C)
10.6ms^-1
23
An incident ray is reflected normally by a plane mirror onto a screen where it forms a bright spot. The mirror and screen are parallel and 1m apart. If the mirror is rotated through 5o, calculate the displacement of the spot
Răspuns
(D)
17.6cm
24
Convex spherical mirrors are preferred to plane mirrors as driving mirrors because
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(B)
it provides a wider field of view
25
An object is placed 20cm from a lens. If an image is formed on a screen 260cm away from the lens, calculate the magnification of the image
Răspuns
(D)
13
26
A piece of cloth appears green in sunlight. When held in red light, it will appear
Răspuns
(D)
black
27
Dispersion of white light by a glass prism occurs because
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(B)
the refractive index of glass is different from each constituent colour of white light
28
Which of the following statements about sound is correct?
Răspuns
(C)
the wavelength of sound changes when it travels from to water
29

The diagram above shows the wire of a sonometer box set into resonance by a vibrating tuning fork of frequency f, when the wire is stretched by a tension T, the resonating length of the wire is I while the wavelength of the sound produced is \(\lambda\). Which of the following statements is not correct? The wave produced on the wire is
Răspuns
(A)
stationary and lonitudinal
30
The diagram above shows the wire of a sonometer box set into resonance by a vibrating tuning fork of frequency f, when the wire is stretched by a tension T, the resonating length of the wire is I while the wavelength of the sound produced is \(\lambda\). Which of the following statements about the frequency of vibration of the wire is not correct?
Răspuns
(A)
proportional to the mass per unit length of the wire
31
If the frequency of the tuning fork at resonance is 256Hz, calculate the frequency of vibration of the wire when the tension in he wire is increased to 196N
Răspuns
(C)
358.4Hz
32
The magnitude of the gravitational force between two particles 0.10m apart is 10N. If the distance between them is increased to 0.20m, calculate the magnitude of the new force
Răspuns
(D)
2.5N
33
As the plates of a charged variable capacitor are moved closer together, the potential difference between them
Răspuns
(B)
decrease
34
What is the effective capacitance in the circuit?
Răspuns
(A)
2\(\mu F\)
35
What is the total energy stored by the capacitors?
Răspuns
(D)
1.0 x 10^-2J
36
Three identical lamps each power 100W are connected in parallel across a potential difference of 250V. Calculate the current in the circuit
Răspuns
(C)
1.2A
37
An electric bulb is rated 60W, 220V. Calculate the resistance of its filament when it is operating normally
Răspuns
(D)
806.7\(\Omega\)
38
The Earth's magnetic equator passes through Jos in Nigeria. At Jos. the
Răspuns
(C)
angle of dip is zero
39
Which of the following statements about magnetic lines of force is not correct?
Răspuns
(C)
magnetic lines of force are closely packed together at neutral point
40
The material used for constructing the core of an electromagnet is
Răspuns
(A)
iron