Question

In an isobaric process, the ratio of heat supplied to the system (dq) and work done by the system (dW) for diatomic gas is:

• A. $5:7$
• B. $1:1$
• C. $7:5$
• D. $7:2$

Answer 1

The correct option is D $7:2$

As, $dE=dW+dq$
$-dW=dq-dE$
So,
$-\frac{dq}{dW}=\frac{dq}{dq-dE}$
$=\frac{n{C}_{P}dT}{n{C}_{P}dT-n{C}_{V}dT}=\frac{C_P}{(C_P-C_V)}$
For diatomic gas, $C_P=\frac{7}{2}Rand{C}_V=\frac{5}{2}R$
So,
$-\frac{dq}{dW}=\frac{7R}{2R}=\frac{7}{2}$