Waec Physics 2005 Past Questions and Answers

Question 21:

• WAEC 2005

Water falls through a height of 50m. Determine the temperature rise at the bottom of the fall. [Neglect energy losses. Specific heat capacity of water = 4200Jkg^-1 K^-1, g = 10ms²]

A. 0.119^oC
B. 0.840^oC
C. 1.190^oC
D. 8.400^oC

Question 22:

• WAEC 2005

The energy required to change a solid to liquid at constant temperature is called

A. Thermal capacity
B. Has lower specific heat capacity
C. Latent heat of fusion
D. Latent heat of vaporisation

Question 23:

• WAEC 2005

Which of the following statements about boiling and evaporation at atmospheric pressure is correct?

A. Evaporation and boiling of water take place at 100^o
B. Evaporation of water takes place at a temperature greater than 100^oC, while boiling takes place at 100^oC
C. Evaporation of water takes place at 100^oC while boiling takes place at a higher temperature
D. Boiling takes place at 100^o while evaporation my take place at temperatures lower than 100^oC

Question 24:

• WAEC 2005

Which of the following statements is correct?

A. The density of a liquid decreases when it expands
B. The density of a liquid increases when the liquids are heated
C. The real expansivity of a liquid is less than its apparent expansivity
D. A liquid changes to solid when heated to a sufficiently high temperature

Question 25:

• WAEC 2005

The pressure exerted by a given mass of gas in a container

A. Decreases if the container is heated
B. Increases if the molecules of the gas move faster
C. Increases if the container is doubled
D. Decreases as the kinetic energy of the gas molecules inceases