JAMB - Physics (1981)

1
The ice and steam points of mercury-in-glass thermometer of centigrade scale and of uniform bore correspond respectively to 3cm and 19cm lengths of the mercury thread when the length is 12cm, the temperature is
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(C)
56^oC
2
A vapour is said to be saturated when?
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(B)
a dynamic equilibrium exists between the liquid molecules and the vapour molecules at a given temperature
3
The latent heat of fusion of a substance is the heat required to
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(C)
change unit mass of substance from solid to liquid at constant temperature
4
The following types of waves are transverse EXCEPT
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(C)
sound waves
5
The principle of transmissibility of pressure in a fluid at rest in all directions is known as
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(D)
Pascal's law
6
When fixed mass of an ideal gas expands at constant temperature, which property of the gas molecule increases?
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(D)
average seperation
7
Which of the following does NOT describe the image formed by a plane mirror?
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(D)
magnified
8
If a source of sound is moving, a stationary listener will hear a sound of different frequency. This is called
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(A)
Doppler effect
9
Which of the following elements are real magnetic materials?
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(A)
Iron, steel and nickel
10
An inclined plane of angle \(\theta\), acting as a simple machine, has a velocity ratio
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(B)
\(\frac{1}{\text{sin}\theta}\)
11
Heat may be transferred by conduction, convection and radiation. By which of these methods does heat travel through vacuum?
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(C)
radiation only
12
Which of the following statements is applicable to a real image formed by a concave mirror? i. it can be observed on a screen ii. it is always inverted and in front of the mirror iii. it only seams to exist IV. it is formed by the actual converging of rays of light
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(B)
i, ii and iv only
13
Which of the following is NOT an effect that can be produced by an electric current?
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(E)
none of the above
14
A cell of e.m.f 2V and internal resistance 1\(\Omega\) supplies a current of 0.5 amps to a resistance whose value is
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(E)
3\(\Omega\)
15
An example of a scalar quantity is
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(C)
electric charge
16
Heat was supplied to a block of ice at 0^oC until half of it melted. Which of the following statements is true?
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(B)
the temperature remains constant and the volume of the ice decreases
17
When a ray of light passes from water to glass, it is
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(B)
bent towards the normal
18
The resistance of a 240V, 60 watt electric filament bulb is
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(E)
960\(\Omega\)
19
An aircraft travelled from calabar to kano as follows: it flew first to ilorin convering a distance of 300km, 30^o west of North, and then flew 400km, 60^o East of North to kano. What is the resultant displacement?
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(D)
500km
20
All of the following frequencies are overtones of 320 Hz EXCEPT
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(C)
520Hz
21
The driver in a motor car, of which the total mass is 800kg and which is traveling at 20ms-1, suddenly observes a stationary dog in his path 50m ahead. If the car brakes can exert a force of 2000N, what will most likely happen?
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(B)
the car will stop 30m after hitting the dog
22
The absolute refractive indices of glass and water are \(\frac{3}{2}\) and \(\frac{4}{3}\) respectively. The refractive index at the interface when a ray travels from water to glass is
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(C)
\(\frac{9}{8}\)
23
Which of the following statements is CORRECT?
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(C)
the magnitude of any charge is a multiple of the charge of an electron
24
Which type of radiation does not NOT originate within the nucleus?
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(E)
x-rays
25
Which type of radiation does not NOT originate within the nucleus?
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(E)
x-rays
26
The resistance of an open series circuit is
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(E)
infinite
27
The lack of power of accommodation which is mainly due to the hardening of the eye lens and is usual with onset of old age is called?
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(C)
presbyopia
28
A body falls freely under gravity (g = 9.8ms^-2) from a height of 40m on to the top of a platform 0.8m above the ground. Its velocity on reaching the platform is
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(E)
27.7ms^-1
29
Alternating current can induce voltage because it has a
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(B)
varying magnetic field
30
Two particles X and Y starting from rest cover the same distance. The acceleration of X is twice that of Y. the ratio of the time taken by X to that taken by Y is
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(C)
\(\frac{1}{\sqrt2}\)
31
a balloon inflated with helium gas at ground level is released. As it rises through a constant temperature atmosphere.
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(B)
te product of pressure and volume remains constant
32
Change of state is accompanied by change of?
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(E)
volume and heat content
33
The quantity (timbre) of sound depends on
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(C)
harmonics
34
The mass of a proton is approximately equal to that of
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(E)
a neutron
35
An object placed on the principle axis of a convex lens of focal length 10m produces a real image of double magnification. The image distance from the lens is
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(A)
30cm
36
A liquid-in-glass thermometer should quickly register temperature changes. This is achieved by choosing a liquid that
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(D)
has a high thermal conductivity
37
The extension in a spring when 5g wt was hung from it was 0.56cm. If Hooke's law is obeyed, What is the extension caused by a load of 20g wt?
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(E)
2.24cm
38
Which of the following is NOT directly associated with direct current (DC)?
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(C)
a transformer
39
The relationship between the period T and the length l of a simple pendulum is T = 2\( \pi \) \( ( \frac{I}{g}) ^{ \frac{1}{2} } \). From experiment data of T and I, one can obtain the following graphs, i. T vs.I ii. T vs I2 iii. T2 vs. I iv. T vs \( \sqrt{I} \) v. logT vs logI. Which of the following graphs, are linear?
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(D)
iii, iv and v
40
A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil.If the input voltage is 100 volts, the output voltage is
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(B)
10 volts
41
A closed coil of wire is placed near a magnet. The magnet lies along the axis of the coil. Under which of the following conditions would there be no current in the coil?
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(D)
when both the coil and the magnet are held stationary
42
If I is the current passing through a metallic resistor and H is the rate of Heat generated in the resistor at a constant temperature, then
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(D)
H \(\alpha\) I²
43
A solid weighs 4.8g in air, 2.8g in water and 3.2g in kerosine. The ratio of density of the solid to that of the kerosine is
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(B)
3
44
A body of mass 6kg rests on an inclined plane. The normal reaction is R and the limiting frictional force is F as shown in the image above. if F = 30N, and g = 10ms² then the angle of inclination \( \theta \) is
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(B)
\( 30^{\circ} \)
45
The effect of closing the key K in the circuit shown above would be to
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(C)
increase the current by 0.4A