Physics Past Questions and Answers

What is the difference in the amount of heat given out by 4kg of steam and 4kg of water when both are cooled from 100^oC to 80^oC? [the specific latent heat of steam is 2,260,000Jkg^-1, specific heat capacity of water is 4200Jkg^-1K^-1]

A 4200J
B 2,260,OOOJ
C 9,040,000J
D 9,380,000J

Question 17:

How long does it take a 750W heater to raise the temperature of 1kg of water from 20^oC to 50^oC [specific heat capacity of water = 4200Jkg^-1K^-1]

A 84s
B 112s
C 168s
D 280s

Question 18:

The saturated vapour pressure of a liquid increases as the

A Volume of the liquid increases
B Volume of the liquid decreases
C Temperature of the liquid increases
D Temperature of the liquid decreases

Question 19:

The absolute temperature of a perfect gas is proportional to the average

A Potential energy of the molecules
B Seperation between the molecules
C Kinetic energy of the molecules
D Velocity of the molecules

Question 20:

A room is heated by means of a charcoal fire, An occupant of the room standing away from the fire is warmed mainly by

A Convection
B Radiation
C Conduction
D Reflection