Topic: Thermodynamics
The efficiency $\eta$ of any heat engine and efficiency $\eta_{R}$ of a reversible heat engine operating between common heat source and heat sink are related as
- A. $\eta>\eta_{R}$
- B. $\eta<\eta_{R}$
- C. $\eta\ge\eta_{R}$
- D. $\eta\le\eta_{R}$
Answer: D. $\eta\le\eta_{R}$
Explanation: Let $\eta$ = efficiency of any heat engine and $\eta_{R} =$ efficiency of Reversible heat engine. According to Carnot's principle, no engine can be more efficient than a reversible engine operating between the same two thermal reservoirs. So, $\eta\le\eta_{R}$.