Waec Physics 1998 Past Questions and Answers

Question 16:

• WAEC 1998

The average kinetic energy of the molecules of a perfect gas is directly proportional to the

A. Pressure exerted by the gas
B. Volume of the gas molecule
C. Kelvin temperature of the gas
D. Volume of the gas container
E. Celcius temperature of the gas

Question 17:

• WAEC 1998

How much heat is emitted when a body of mass 200g cools from 37^oC to 31^oC? (specific heat capacity of the body = 0.4Jg^-1K^-1,)

A. 4800J
B. 1200J
C. 480J
D. 202J
E. 80J

Question 18:

• WAEC 1998

If the cubic expansivity of brass between 27^oC and 100^oC is 5.7 x 10^-5K^-1, What is its linear expansivity?

A. 2.85 x 10^-5K^-1
B. 1.90 x 10^-5K^-1
C. 1.86 x 10^-5K^-1
D. 1.70 x 10^-5K^-1
E. 1.63 x 10^-5K^-1

Question 19:

• WAEC 1998

Air at temperature 527^oC and pressure 30 atmospheres is admitted into the cylinder of an engine. Calculate the pressure of the gas when it has expanded to 5 times its volume and cooled to 127^oC as it leaves the engine

A. 1.5 atmospheres
B. 2.5 atmospheres
C. 3.0 atmospheres
D. 12.8 atmospheres
E. 15.0 atmospheres

Question 20:

• WAEC 1998

The inside of a vacuum flak is usually coated with silver to reduce heat loss by

A. Evaporation
B. Radiation
C. Conduction
D. Convention
E. Condensation