The temperature inside a refrigerator is $t_2 \, ^\circ C$ and the room temperature is $t_1 \, ^\circ C$. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be:

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

The temperatures inside and outside of a refrigerator are $260 \ K$ and $315 \ K$ respectively. Assuming that the refrigerator cycle is reversible,calculate the heat delivered to the surroundings for every joule of work done. (in $.73$)

In a refrigerator,one removes heat from a lower temperature and deposits it to the surroundings at a higher temperature. In this process,mechanical work has to be done,which is provided by an electric motor. If the motor is of $1\,kW$ power and heat is transferred from $-3\,^{\circ}C$ to $27\,^{\circ}C$,find the heat taken out of the refrigerator per second,assuming its efficiency is $50\%$ of a perfect engine.

An ideal heat engine has an efficiency $\eta$. The coefficient of performance of the engine when driven backward will be

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 ........ $^{\circ}C$.