1992 - WAEC Physics Past Questions and Answers - page 2
11
A body of mass 5kg falls from a height of 10m above the ground. What is the kinetic energy of the body just before it strikes the ground? (Neglect energy losses and take gas 10ms2)
A
5J
B
25J
C
250J
D
500J
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12
Steel bars, each of length 3.0 m at 28°C, are to be used for constructing a rail line. If the linear expansivity of steel is 1.0 x 10-5°C, what is the safety gap that must be left between successive bars if the highest temperature expected is 40oC?
A
1.2 x 10-1cm
B
8.4 x 10-2cm
C
7.2 x10-2cm
D
3.6 x 10-2cm
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13
Which of the following statements is/are correct? I. Pure water freezes at 0oC under normal pressure ll. Water has its highest density at 4oC. III. The volume at 4oC,
A
I only
B
II only
C
I and II only
D
I and III only
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14
A given mass of gas at a temperature of 30°C is trapped in a tube of volume V. Calculate the temperature of the gas when the volume is reduced to two-third of its original value by applying a pressure twice the original value.
A
71oC
B
40oC
C
131oC
D
313oC
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15
Which of the following colours of surfaces will radiate heat energy best?
A
Red
B
White
C
Black
D
Yellow
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16
A gas which obeys Charles’ law exactly has a volume of 283cm3 at 10oC. What is its volume at 30oC?
A
142cm3
B
293cm3
C
303cm3
D
566cm3
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17
Which of the following best explains why a person suffers a more severe burn when his skin is exposed to steam than when boiling water pours on his skin?
A
Steam is at a higher temperature than boiling water
B
Steam possesses greater heat energy per unit mass than boiling water
C
Steam spreads more easily over a wider area of the skin man boiling water
D
Steam penetrates more deeply into the skin than boiling water
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18
A small circular membrane is 10cm below the surface of a pool of mercury when the barometric height is 76 cm of mercury. If the density of mercury is 13600\(kgm^{-3}\), what is the pressure on the membrane in \(Nm^{-2}\)? \((g =10ms^{-2})\)
A
1.17 x 107 Nm-2
B
6.80 x 105Nm-2
C
1.17x105Nm-2
D
1.03 x 105Nm-2
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19
Which of the following instruments is used to measure relative humidity?
A
Hydrometer
B
Barometer
C
Manometer
D
Hypsometer
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20
A metal of mass 1.5 kg was heated from 27oC to 47oC in 4 minutes by a boiling ring of 75 W rating. Calculate the specific heat capacity of the metal, (Neglect heat losses to the surrounding)
A
2.5 X103J kg-10C-1
B
6.0 X102J kg-10C-1
C
2.5 x 102J kg-10C-1
D
1.4 X102J kg-10C-1
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