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Multiple Choice
Freezing a kilogram of water, initially at 20°C, requires your refrigerator to remove about of thermal energy from the water. If the coefficient of performance of your refrigerator is 5.0, how much heat is exhausted into your kitchen when you freeze a kilogram of water?
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Verified step by step guidance
1
Understand the concept of the coefficient of performance (COP) for a refrigerator, which is defined as the ratio of the heat removed from the cold reservoir (Q_c) to the work input (W). Mathematically, COP = Q_c / W.
Given that the COP of the refrigerator is 5.0 and the heat removed from the water (Q_c) is 417 kJ, use the formula to find the work input: W = Q_c / COP. Substitute the given values into the equation.
Calculate the work input (W) using the values: W = 417 kJ / 5.0.
The heat exhausted into the kitchen (Q_h) is the sum of the heat removed from the water (Q_c) and the work input (W). Use the formula: Q_h = Q_c + W.
Substitute the values of Q_c and W into the equation to find Q_h: Q_h = 417 kJ + (417 kJ / 5.0).