Question

P-V diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be

• A. $4R$
• B. $2.5R$
• C. $3R$
• D. $\frac{4R}{3}$

Answer 1

The correct option is C $3R$

P-V diagram is a straight line passing through the origin.

Hence, $P\propto V$

$P{V}^{-1}=constant$

Molar heat capacity for $P{V}^x=constant$

So, $x=-1$

$C=\frac{R}{\gamma -1}+\frac{R}{1-x}$

$C=\frac{R}{1.4-1}+\frac{R}{1+1}=\frac{5R}{2}+\frac{R}{2}$

$C=\frac{6R}{2}=3R$

The correct option is C.