Freezing compartment of a refrigerator is at $0^{\circ} C$ and room temperature is $27.3^{\circ} C$. Work done by the refrigerator to freeze $1 \ g$ of water at $0^{\circ} C$ is $(L_{\text{ice}} = 80 \ cal \ g^{-1})$. (in $J$)

$A$ Carnot engine having an efficiency of $\frac{1}{10}$ is being used as a refrigerator. If the work done on the refrigerator is $10 \; J,$ the amount of heat absorbed from the reservoir at lower temperature is .............. $J$.

$A$ refrigerator with a coefficient of performance of $1/3$ releases $200 \ J$ of heat. What is the work done on the working substance in Joules?

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 $W$)

Why can the coefficient of performance of a refrigerator never be infinite?

For a refrigerator,heat absorbed from the cold reservoir (sink) is $500\, J$ and heat rejected to the hot reservoir (source) is $800\, J$. The coefficient of performance is: