WAEC - Physics (2010)

1
Which of the following properties of a long steel bar would alter if the bar were melted, recast into a cube and allowed to cool to its original temperature?
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(B)
volume
2
Which of the following instruments is best for measuring the diameter of a thin constantan wire?
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(C)
micometer screw guage
3
What is the density of a fuel of relative density 0.72? [Density of water = 1000kg m^-3]
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(B)
720 kgm^-3
4
The types of motion which a cylindrical drum rolling down an inclined plane undergoes are
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(B)
rotational and translational
5
Which of the following statements about static friction is correct? It
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(C)
depends on the relative motion between the surface in contact
6
Which of the following statements about moving particle is correct?
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(A)
if the resultant force acting on the particle is zero, then it is in dynamic equillibrium
7
Two cars X and Y travelling in opposite directions along the same high way at uniform velocities 110 kmh^-1 and 90kmh^-1 respectively pass each other at a certain point. The velocity of X relative to Y at the time they pass each other is
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(A)
200 kmh^-1
8
The average speed of an object is determined by dividing the sum of its initial and final speeds by two only when the acceleration is
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(B)
uniform
9
a body is projected horizonatlly from the top of a cliff 45m above the ground. if the body lands at a distance 30m from the foot of the cliff, calculate the speed of projection. [g = 10ms-2]
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(A)
10ms^-1
10
Which of the following statements best describes a rigid body? A body which
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(A)
is not equally deformed
11
simple harmonic oscillator has a period of 0.02s and amplitude of 0.25m. Calculate the speed in ms^-1 at the centre of the oscillation
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(B)
25.00\(\pi\)
12
A vertical string, suspended from a fixed point and having a small mass attached to the free end is set into oscillations. Which of the following statements about the system are correct? i. The potential energy of the mass is a minimum at the middle of the swing ii. Its kinetic energy is a maximum at the middle of the swing iii. The sum of the potential and kinetic energies is constant throughout the swing
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(C)
ii and iii only
13
A moving body of mass 25.0kg undergoes a uniform retardation of 20.0ms^-2. Calculate the magnitude of the retardating force
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(D)
500.00N
14
Which of the following sources of energy is/are exhausible? i. Solar ii. Fossil fuels iii. Tidal power
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(D)
ii only
15
a machine is said to be a third class lever when the
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(C)
effort is between the fulcrum and load
16
a thermometer records 680 mmHg at steam point and 440 mmHg at ice point. The temperature it records at 380 mmHg is
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(A)
-25^oC
17
The advantages of the thermoelectric thermometer include the following characteristics except that it
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(D)
is fairly sensitive
18
In a thermos flask, heat loss by radiation is minimizes by the
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(A)
silvered surfaces
19
The pressure P, volume V, and absolute temperature T of a given mass of an ideal gas change simultaneously. Which of the followng equations is correct about the gas?
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(D)
\(\frac{I}{T} = \frac{constant}{PV}\)
20
Specific heat capacity 36.4 Jkg-1 K-1 of a body means that when 36.4J of heat energy is supplied to a body of
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(C)
mass 1kg, the temperature rises by 1K
21
An electric drill rated 400W is used to drill a hole in copper of mass 400g in 20s. Calculate the rise in temperature if all the heat produced is absorbed by the copper. [specific heat capacity of copper = 400Jkg^-1K^-1]
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(C)
50^oC
22
A solid of mass 0.5kg initially at 50^oC melts at 60^oC. Calculate the quantity of heat required to melt it completely. [specific heat capacity of the solid =2.0KJ kg^-1K^-1][Specific latent heat of fusion of solid =1.0 KJ kg^-1]
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(C)
10500J
23
Dew point is not affected by
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(B)
wind
24
A certain wave has a speed of 20ms^-1. If the frequency of the wave is 0.25Hz, calculate the distance between successive crests of the wave
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(D)
80.0m
25
The ability of a wave to spread around corners is called
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(C)
diffraction
26
The following devices use plane mirrors in their operations, except
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(D)
binoculars
27
When an object is placed at the principal focus of a concave mirror, the location of the image formed is
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(C)
at infinity
28

From the diagram, the correct equation for the refractive index n of the medium is
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(A)
n = tan i
29
A ray of light travels from air to water. The refeactive index of water is given by the expression
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(D)
\(\frac{\text{wavelength in air}}{\text{wavelength in water}}\)
30
A lens that is thinner at the middle and thicher at the edges is
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(A)
diverging
31
Which of the following electromagnetic wave has the longest wavelength?
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(A)
radio-waves
32
The amplitude of a sound wave determines its
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(C)
loudness
33
As the air column of length L in an air pipe decreases, the frequency of the sationary wave emitted
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(A)
decreases
34
A positively charged glass rod is placed near the cap of a positively charged electroscope. The divergence of the leaf is observed to
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(B)
increase
35
Capacitors are used in the following devices, except
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(C)
electric irons
36
Use the diagram above to calculate the current, I.
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(B)
0.97A
37

Determine the potential difference. V across the parallel resistors
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(B)
2.3V
38
A galvanometer of internal resistance 50\(\Omega\) and full scale deflection of 20 mA is converted into a voltmeter by connecting a resistor of resistance 1950\(\Omega\) in series to it. Calculate the maximum voltage that can be read by the voltmeter
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(D)
40V
39
In the wiring of houses, the fuse is connected to the wire coloured
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(B)
brown
40
Which of the following factors does not affect the electric resistance of wire?
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(B)
mass
41
Which of the following factors will increase the sensitivity of moving coil meter?
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(D)
soft iron core
42
In order to prevent bar magnets from losing their strength, they are stored wih keepers such that the two bars are placed with
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(C)
unlike poles facing each other and the keepers placed at their ends
43
The energy, E stored in an inductor of inductance L when current I passes through it is given by the equation
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(B)
E = LI²
44
The resonant frequency of an a.c circuit is 1000 kHz. If each of the capacitance and inductance in the circuit is reduced by 50%, and no other changes are made, the resonant frequency will become
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(D)
2000kHz
45
Eddy currents can be reduced by
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(C)
creating holes in the metal plates