Question

One of the most efficient engines ever developed operates between $2100K$ and $700K$. Its actual efficiency is $40\%$. What percentage of its maximum possible efficiency is this?

• A. $40\%$
• B. $60\%$
• C. $66.67\%$
• D. $33.37\%$

Answer 1

Answer: (B)

$60\%$

Maximum efficiency depends only on Cold and Hot region temperatures.

$\therefore \eta =1-\frac{T_C}{T_H}=1-\frac{700}{2100}=66.67$%

percentage of actual efficiency to its maximum possible efficiency

=$\frac{40}{66.67}\times 100=60\%$

Hence,option B is correct