One quality of a thermometer is that its heat capacity should be small. If $P$ is a mercury thermometer,$Q$ is a resistance thermometer,and $R$ is a thermocouple type,then:

The temperature at which the vapour pressure of a liquid becomes equal to the external (atmospheric) pressure is its

$A$ water cooler of storage capacity $120$ litres can cool water at a constant rate of $P$ watts. In a closed circulation system (as shown schematically in the figure),the water from the cooler is used to cool an external device that generates constantly $3 \text{ kW}$ of heat (thermal load). The temperature of water fed into the device cannot exceed $30^{\circ}\text{C}$ and the entire stored $120$ litres of water is initially cooled to $10^{\circ}\text{C}$. The entire system is thermally insulated. The minimum value of $P$ (in watts) for which the device can be operated for $3$ hours is (Specific heat of water is $4.2 \text{ kJ kg}^{-1} \text{K}^{-1}$ and the density of water is $1000 \text{ kg m}^{-3}$)

$A$ block of ice at $-20\,^oC$ having a mass of $2\, kg$ is added to $3\, kg$ of water at $15\,^oC$. Neglecting heat losses and the heat capacity of the container,which of the following is true?

$A$ lead ball moving with a velocity $V$ strikes a wall and stops. If $50\%$ of its energy is converted into heat,then what will be the increase in temperature? (Specific heat of lead is $S$)

$A$ closed bottle containing water at $30^{\circ} C$ is opened on the surface of the moon. Then,