Question

A diatomic gas $(\gamma =1.4)$ does 200 J of work when it is expanded isobarically. Find the heat given to the gas in the process.

• A. 500 J
• B. 700 J
• C. 600 J
• D. 900 J

Answer 1

The correct option is B 700 J

First law of thermodynamics is:
$Q=p\Delta V+n{C}_v\Delta T$

$=p\Delta V+n\frac{R}{\gamma -1}\Delta T=p\Delta V(1+\frac{1}{\gamma -1})=200(1+\frac{1}{0.4})=200\times 3.5=700J$