If the door of a refrigerator is kept open in a room,will it make the room warm or cool?

$A$ 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 ..... $J$

When does any refrigerator or heat pump work?

The temperature of the freezer compartment of an ideal refrigerator is $-13 \, ^\circ C$. If the coefficient of performance of the refrigerator is $5$,then the temperature of the surroundings (to which heat is rejected) is:

$A$ 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 .............. $J$.

The specific heat capacity of a metal at low temperature $T$ is given as $C_p = 32 \left( \frac{T}{400} \right)^3 \text{ kJ K}^{-1} \text{ kg}^{-1}$. $A$ $100 \text{ g}$ vessel of this metal is to be cooled from $20 \text{ K}$ to $4 \text{ K}$ by a special refrigerator operating at room temperature $27^\circ \text{C}$. The amount of work required to cool the vessel is