$A$ refrigerator with a coefficient of performance $0.25$ releases $250 \, J$ of heat to a hot reservoir. The work done on the working substance is

The coefficient of performance of a refrigerator working at a temperature of $27^{\circ} C$ is $5$. Find the temperature inside the refrigerator. (in $K$)

In a cold storage,ice melts at the rate of $2 \ kg$ per hour when the external temperature is $20^{\circ} C$. The minimum power output of the motor used to drive the refrigerator which just prevents the ice from melting is (latent heat of fusion of ice $= 80 \ cal \ g^{-1}$) (in $W$)

When does any refrigerator or heat pump work?

The specific heat capacity of a metal at low temperature $T$ is given as $C_p = 32 \left( \frac{T}{400} \right)^3 \text{ kJ K}^{-1} \text{ kg}^{-1}$. $A$ $100 \text{ g}$ vessel of this metal is to be cooled from $20 \text{ K}$ to $4 \text{ K}$ by a special refrigerator operating at room temperature $27^\circ \text{C}$. The amount of work required to cool the vessel is

The temperature of the freezer compartment of an ideal refrigerator is $-13 \, ^\circ C$. If the coefficient of performance of the refrigerator is $5$,then the temperature of the surroundings (to which heat is rejected) is: