A cup of tea cools from $65.5^{\circ} \mathrm{C}$ to $62.5^{\circ} \mathrm{C}$ in 1 min in a room at $22.5^{\circ} \mathrm{C}$. How long will it take to cool from $46.5^{\circ} \mathrm{C}$ to $40.5^{\circ} \mathrm{C}$ in the same room?

A Carnot engine takes 300 calories of heat from a source at 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is

Pressure of an ideal gas is increased by keeping temperature constant. The kinetic energy of molecules