$A$ refrigerator of coefficient of performance $5$ that extracts heat from the cooling compartment at the rate of $250 \ J$ per cycle is placed in a room. The heat released per cycle to the room by the refrigerator is (in $J$)

$A$ Carnot freezer takes heat from water at $0\,^{\circ}C$ inside it and rejects it to the room at a temperature of $27\,^{\circ}C$. The latent heat of ice is $336 \times 10^3\, J\,kg^{-1}$. If $5\, kg$ of water at $0\,^{\circ}C$ is converted into ice at $0\,^{\circ}C$ by the freezer,then the energy consumed by the freezer is close to

If the sink and source temperatures of a refrigerator are $4^{\circ} C$ and $15^{\circ} C$ respectively,then the efficiency of the refrigerator is:

When does any refrigerator or heat pump work?

If the door of a refrigerator is kept open,then which of the following is true?

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