Question

A Carnot's engine used first an ideal monoatomic gas then an ideal diatomic gas. If the source and sink temperature are $411^{o}C$ and $69^{o}C$ respectively and the engine extracts 1000 J of heat in each cycle, then area enclosed by the PV diagram is

• A. 100 J
• B. 300 J
• C. 500 J
• D. 700 J

Answer 1

Answer: (C)

500 J

Answer 2

$\eta = 1 - \frac{T_{2}}{T_{1}} = 1 - \frac{(273 + 69)}{(273 + 411)} = 0.5$

⇒ Work done $= \eta \times Q = 0.5 \times 1000 = 500J$