Waec Physics 1999 Past Questions and Answers

Question 16:

• WAEC 1999

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.

Question 17:

• WAEC 1999

The temperature of a piece of metal of mass 9 g is raised from 10^oC to 110^oC 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

Question 18:

• WAEC 1999

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.

Question 19:

• WAEC 1999

Calculate the heat energy required to change 0.1kg of ice at 0^oC to water boiling at 100^oC. (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.

Question 20:

• WAEC 1999

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.