Question

A heat engine operates between $2100K$ and $700K$. Its actual efficiency is $40\%$. What percentage of its maximum possible efficiency is this?

• A. $66.67\%$
• B. $60\%$
• C. $40\%$
• D. $33.33\%$

Answer 1

The correct option is B $60\%$

The efficiency of the engine is given as $1-\frac{T_2}{T_1}=1-\frac{700}{2100}=1-\frac{1}{3}=66.67\%$.

But the actual efficiency if given as $40\%$.

Now to calculate how much percentage is the actual efficiency of its maximum possible efficiency we get $\frac{40}{66.67}\times 100=60\%$.