Final answer:
The efficiency of a reversible engine cannot exceed 1.0, while the coefficient of performance (COP) of a reversible refrigerator is always greater than or equal to 1.0, thus the answer is (c) No, Yes.
Step-by-step explanation:
The efficiency of a reversible engine cannot exceed 1.0; this is a consequence of the second law of thermodynamics, which states that it is impossible to have a process whose sole result is the transfer of heat from a cooler body to a hotter one without any work input.
Therefore, all reversible engines operating between the same two reservoirs have the same efficiency, and it cannot be greater than that of a Carnot engine, which is the most efficient. Since the efficiency is defined as the work output divided by the heat input, and because no engine can output more work than the heat energy it receives, the efficiency is always less than or equal to 1.
Similarly, the coefficient of performance (COP) of a reversible refrigerator must be greater than or equal to 1. The COP is defined as the amount of heat removed from the cold reservoir (cooling effect) divided by the work input required to achieve that effect.
Because a refrigerator moves heat from a cold space to a warmer space, it requires less work to transfer an equivalent amount of heat compared to the output of heat, which inherently gives it a coefficient of performance greater than 1.
Therefore, the correct answer to the question is (c) No, Yes.