Question

The fundamental limitation to the coefficient of performance of a refrigerator is given by

• A. first law of thermodynamics
• B. Newton’s law of cooling
• C. zeroth law of thermodynamics
• D. second law of thermodynamics

Hint:

Always relate performance limits of thermal systems to the second law of thermodynamics—it governs all realistic thermal engine operations.

Answer 1

The Correct Option is D

Step 1: Understanding coefficient of performance (COP): 
COP is a measure of the efficiency of a refrigerator and is defined as:
\[ COP = \frac{Q_L}{W} \] where \( Q_L \) is the heat extracted from the cold reservoir and \( W \) is the work input. 
Step 2: Role of thermodynamic laws: 
The second law of thermodynamics sets a fundamental upper limit on the efficiency (COP) of heat engines and refrigerators.
It states that no process is possible in which the sole result is the absorption of heat from a reservoir and its complete conversion into work. Hence, COP cannot be infinite or exceed the Carnot limit.