In a refrigerator operating on a reversed Carnot cycle between -13 °C (260 K) and 27 °C (300 K), what is the theoretical coefficient of performance (COP)?
Answer and explanation
Correct answer: B. 6.5
- Step 1: COP of Carnot refrigerator: COP = T_C / (T_H - T_C). Step 2. T_C = 260 K, T_H = 300 K. Step 3. T_H - T_C = 300 - 260 = 40 K. Step 4. COP = 260 / 40 = 6.5. Answer: 6.5. Why not the others: 0.15 is 1/COP; 8.7 uses T_H / 40.
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