(a) When two bodies at different temperatures T${}_1$ and T${}_2$ are brought in thermal contact, the body at the higher temperature lose heat to the body at the lower temperature till the temperatures of both the bodies become equal. The equilibrium temperature is equal to the mean temperature (T${}_1$ + T${}_2$)/2 only when both the bodies have equal thermal capacities.

b) The coolant in a chemical or nuclear plant should have high specific heat. This is because of the coolant with a high specific heat has a high heat-absorbing capacity and vice versa. Hence, a liquid having a high specific heat is the best coolant to be used in a nuclear or chemical plant. This would prevent different parts of the plant from getting too hot.

c) Because of the motion of the air molecules the air temperature inside the car tyre increases when the car is in motion. According to Charles’ law, the temperature is directly proportional to pressure. Hence, if the temperature inside a tyre increases, then the air pressure in it will also increase.

d) Because of the relative humidity in a harbour town more than that in a desert town, a harbour town has a more temperate climate (i.e., without the extremes of heat or cold) than a town located in a desert at the same latitude.