Does a refrigerator full of food consume more power if the room temperature is $\mathbf{20}\mathbf{°}\mathbf{}\mathbf{C}$than if it is$\mathbf{15}\mathbf{°}\mathbf{}\mathbf{C}$? Or is the power consumption the same? Explain your reasoning.

The coefficient of performance of the refrigerator is inversely proportional to the temperature difference between the room temperature and the temperature of the food inside the refrigerator.

Expression for the coefficient of performance of the refrigerator,

$\mathrm{COP}=\frac{\mathrm{T}}{{\mathrm{T}}_0‐\mathrm{T}}$

When the room temperature is increased from$15°\mathrm{C}$ to$20°\mathrm{C}$ , the coefficient of performance of the refrigerator decreases. Therefore, more amount of work is required for the refrigeration process. It means the refrigerator consumes more power if the room temperature is $20°\mathrm{C}$than if it is $15°\mathrm{C}$.

Therefore, the coefficient of performance of the refrigerator decreases with increase in room temperature therefore it consumes more power if the room temperature is $20°\mathrm{C}$.