Chapter 24, Problem 56A

A certain heat engine takes in 25 kJ of heat and exhausts 17 kJ. Chris says that the efficiency of the engine is 0.32. Confirm his findings.

To determine

To verify: The findings of person C.

Answer to Problem 56A

Yes, it is the same. The efficiency is 0.32.

Explanation of Solution

Given:

A heat engine takes25 kJ heat while exhausts17 kJ heat.

Formula used:

The efficiency of a heat engine is

  $\eta =\frac{{\text{Q}}_{\text{source}}{\text{-Q}}_{\text{sink}}}{{\text{Q}}_{\text{source}}}$

Calculation:

Efficiency of a heat engine operating between 25 kJ and 17 kJ of heat is

  $\eta =\frac{25\text{ kJ}-\text{17 kJ}}{25\text{ kJ}}=\frac{8}{25}=0.32$

Conclusion:

Thus, results obtained by calculation and those predicted by person C is same and equal to $0.32$ .