If the coefficient of performance of a refrigerator is $\beta$ and the heat absorbed from the refrigerated space is $Q$,then the work done on the system is:

The coefficient of performance of a refrigerator is $5$. If the temperature inside the freezer is $-20^{\circ}C$,the temperature of the surroundings to which it rejects heat is ........ $^{\circ}C$.

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 $W$)

$A$ Carnot heat engine has an efficiency of $10 \%$. If the same engine is worked backward to obtain a refrigerator,then the coefficient of performance of the refrigerator is

If the door of a refrigerator is kept open in an insulated room,the temperature of the air in the room will . . . . . .

$A$ Carnot's engine works as a refrigerator between $250\, K$ and $300\, K$. It receives $500\, cal$ heat from the reservoir at the lower temperature. The amount of work done in each cycle to operate the refrigerator is ..... $J$