1999 - WAEC Physics Past Questions and Answers - page 2
11
A trolley of mass 4kg moving on a smooth horizontal platform with a speed of 1.0ms-1 collides perfectly with a stationary trolley of the same mass on the same platform. Calculate the total momentum of the two trolleys immediately after the collision.
A
0.5Ns
B
1.0Ns
C
4.0Ns
D
8.0Ns
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12
The ice point of an ungraduated mercury-in-glass thermometer is X, while its steam point is 90o. This thermometer reads 60o when the true temperature is 40oC Calculate the value of X.
A
60o
B
48o
C
40o
D
30o
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13
Iron at 30oC feels colder to the hand than wood at 28oC because
A
their linear expansivities are not equal.
B
the temperature of the iron is higher than that of the wood
C
iron is a better radiator of heat than wood
D
iron conducts heat more quickly from the hand than wood
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14
An iron rod of length 50m and at a temperature of 60oC is heated to 70oC. Calculate its new length. (Linear expansivity of iron = 1.2 x 10-5K-1)
A
50.006m
B
50.060m
C
51.600m
D
51.200m
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15
The heat capacity of a substance is the energy
A
required to raise the temperature of a unit mass of the substance by one degree.
B
required to raise the temperature of the substance by one degree
C
absorbed by the substance at constant temperature
D
lost by a unit mass of the substance.
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16
The temperature of a piece of metal of mass 9 g is raised from 10oC to 110oC when it absorbs 108J of heat energy. Determine the specific heat capacity of the metal in J kg-1K-1
A
1.2
B
12.0
C
120.0
D
1200.0
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17
Which of the following statements is not correct?
A
A sea breeze is due to convection in air
B
Cotton materials are better than woollen ones for use in hot weather
C
Convectional currents play an important role in the cooling of the engine of a motor car
D
The vacuum space in a flask helps to reduce heat loss by radiation.
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18
Calculate the heat energy required to change 0.1kg of ice at 0oC to water boiling at 100oC. (Specific heat capacity of water = 4200 J kg-1K-1) (Specific latent heat of fusion of ice = 336,000 J kg-1)
A
75,600J
B
336,000J
C
340,200J
D
378,000J.
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19
Which of the following statements about evaporation is not correct?
A
The rate of evaporation of a liquid varies with temperature
B
The molecules of an evaporating liquid have an average speed
C
Evaporation occurs when faster molecules escape from the surface of a liquid
D
Evaporation takes place inside a liquid.
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20
Calculate the power rating of an immersion heater used for 10 minutes to increase the temperature of 10kg of water by 15K. (Specific heat capacity of water = 4200 J l-1
A
1,050W
B
16,800W
C
18,060W
D
20,160W
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