Which of the following can be the coefficient of performance of a refrigerator?

If the door of a refrigerator is kept open in an insulated room,the temperature of the air in the room will . . . . . .

In a refrigerator,heat is removed from a low-temperature reservoir and deposited at a high-temperature reservoir. This requires mechanical work,which is provided by an electric motor. If the motor power is $1 \ kW$ and heat is transferred from $-3^{\circ} C$ to $27^{\circ} C$,calculate the heat removed from the refrigerator per second,assuming the efficiency is $50\%$ of the ideal Carnot refrigerator. (in $kJ/s$)

Draw a schematic representation of a refrigerator.

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 $.73$)

$A$ 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 ..... $J$