If a heat engine does 672 J of work from a heat reservoir of 1,600 J, then what is the efficiency of the

Question

heat engine?
answers:
42%

92%

58%

38%

Answer 1

The efficiency (\( \eta \)) of a heat engine is calculated using the formula:

\[ \eta = \frac{W}{Q_h} \]

where \( W \) is the work done by the engine and \( Q_h \) is the heat extracted from the hot reservoir.

Given:

• Work done (\( W \)) = 672 J
• Heat from the reservoir (\( Q_h \)) = 1,600 J

Now, we can substitute the values:

\[ \eta = \frac{672 , \text{J}}{1,600 , \text{J}} \]

Calculating this gives:

\[ \eta = 0.42 \]

To express this as a percentage, we multiply by 100:

\[ \eta = 0.42 \times 100 = 42% \]

Thus, the efficiency of the heat engine is 42%.