12.3 Explain why

(a) Two bodies at different temperatures T1 and T2 if brought in thermal contact do not necessarily settle to the mean temperature (T1 + T2 )/2.

 

(b) The coolant in a chemical or a nuclear plant (i.e., the liquid used to prevent the different parts of a plant from getting too hot) should have high specific heat.

 

(c) Air pressure in a car tyre increases during driving.

 

(d) The climate of a harbor town is more temperate than that of a town in a desert at the same latitude.

Two moles of helium gas are taken over the cycle ABCDA as shown below in P-T diagram. Assuming the gas to be ideal, the work done on the gas in taking from A to B is

Heat is supplied to an ideal monoatomic gas at constant pressure. The ratio of

An ideal engine whose efficiency is 40%, receives heat at 500 K. If required efficiency is 50%, then intake temperature for the same exhaust temperature is

Choose the correct statement.

Two waves of wavelength 50 cm and 51 cm produced 12 beats per second. The velocity of sound is