A household refrigerator is advertised to remove of energy as heat from its interior…

PHYSICS · Multi-part · A Level · Physics · Engineering physics · Engineering physics

Problem

A household refrigerator is advertised to remove

600\,\text{J}

of energy as heat from its

275\,\text{K}

interior while discharging

750\,\text{J}

of energy as heat to the surrounding kitchen air at

300\,\text{K}

. The manufacturer claims that the device requires only

150\,\text{J}

of electrical work per operating cycle. (a) Calculate the coefficient of performance (COP) claimed by the manufacturer. (b) Determine the maximum possible COP for any refrigerator operating between

275\,\text{K}

and

300\,\text{K}

. (c) For one operating cycle, compute the total entropy change of the universe (refrigerator interior, kitchen air, and any other relevant components) implied by the manufacturer’s numbers. (d) Evaluate whether the manufacturer’s claim is consistent with the second law of thermodynamics, citing evidence from parts (b) and (c).

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