Question

The ratio of work done by an ideal diatomic gas to the heat supplied by the gas in an isobaric process is

• A. $\frac{5}{7}$
• B. $\frac{3}{5}$
• C. $\frac{2}{7}$
• D. $\frac{5}{3}$

Answer 1

Answer: (C)

$\frac{2}{7}$

The work done by an ideal diatomic gas is given as $W=\Delta Q-\Delta U=n{C}_p\Delta T-n{C}_v\Delta T=n\frac{7}{2}R\Delta T-n\frac{5}{2}R\Delta T=nR\Delta T$
heat supplied by the gas in isobaric process is
$Q=n{C}_p\Delta T=n\frac{7}{2}R\Delta T$

Thus we get the ratio as-
$\frac{W}{Q}=\frac{2}{7}$