The coefficient of performance (COP) of a refrigerator operating between 300 K and 250 K is:
Correct answer: A. 5
- A. 5
- B. 6
- C. 4
- D. 3
Explanation
The COP of a refrigerator is given by COP = Tcold / (Thot - Tcold ), where Tcold = 250 K and Thot = 300 K. Thus, COP = 250 / (300 - 250) = 250 / 50 = 5.
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Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
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