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 $.73$)

By opening the door of a refrigerator placed inside a room,you:

The coefficient of performance of a Carnot refrigerator working between temperatures $30 \, ^\circ\text{C}$ and $0 \, ^\circ\text{C}$ is:

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

$A$ household refrigerator with a coefficient of performance $1.2$ removes heat from the refrigerated space at the rate of $60 \ kJ/min$. What would be the cost of running this fridge for one month $(30 \ days)$, assuming it is used for $4 \ hours$ each day and the cost of one electrical unit is $6 \ Rs.$?

In a mechanical refrigerator, the low temperature coils are at a temperature of $-23^{\circ}C$ and the compressed gas in the condenser has a temperature of $27^{\circ}C$. The theoretical coefficient of performance is