2012 - WAEC Physics Past Questions and Answers - page 2

11
When a body is slightly titled, it is found that its centre of gravity s slightly raised. What is the state of equilibrium of the body?
A
unstable
B
stable
C
neutal
D
cannot be detrmined
correct option: b
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12
A simple pendulum makes 50 oscillations in one minutes. Determine its period of oscillation
A
0.04s
B
0.83s
C
1.20s
D
50.00s
correct option: c
T = \(\frac{t}{n} = \frac{60}{50} = 1.2\)
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13
The tendency for a stationary body to continue to remain at rest when a force is applied to it is known as
A
friction
B
impulse
C
inertia
D
momentum
correct option: c
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14
A resultant force of magnitude 15N acts on a body of mass 250g. Calculate the magnitude of the acceleration
A
0.06 ms-2
B
3.75ms-2
C
16.67ms-2
D
60.00ms-2
correct option: d
g = \(\frac{F}{M} = \frac{15}{0.25} = 60\)
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15
A girl stands on a scale in a lift. If the reading on the scale is less than her weight, then the lift is moving
A
upward at uniform speed
B
upward with uniform acceleration
C
downward with uniform speed
D
downward with uniform acceleration
correct option: d
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16
The S.I unit of heat is
A
joule
B
kelvin
C
watt
D
ampere
correct option: a
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17
A body is pulled through a distance of 500m by a force of 20N. If the power developed is 0.4kW, calculate the time for which the force acts
A
250.0s
B
25.0s
C
2.5s
D
0.5s
correct option: b
t = \(\frac{FS}{P} = \frac{20 \times 500}{0.4 \times 1000}\)

= 25.0s
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18
A metal sheet of area 100cm2 was heated through 70oC. Calculate its new area if the linear expansivity of the metal is 0.000017k-1
A
100.06 cm2
B
100.12cm2
C
100.24cm2
D
100.36cm2
correct option: c
A2 = A1(1 + 2 x \(\theta\))

= 100(1 + 2 x 1.7 x 10-5 + 70)

= 100.238
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19
The thermopile is a device for detecting
A
radioactive radiations
B
adiant energy
C
x-rays
D
the presence of electrons
correct option: b
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20
In the formation of sea breeze. wind blows from
A
sky to land
B
sea to sky
C
land to sea
D
sea to land
correct option: d
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