Question

A diatomic gas obeys the law $P{V}^x$ = constant. For what vale of $x$, it has negative molar specific heat?

• A. $x>1.4$
• B. $x<1.4$
• C. $1<x<1.4$
• D. $0<x<1$

Answer 1

Answer: (C)

$1<x<1.4$

Molar specific heat equation $C=\frac{R}{y-1}+\frac{R}{1-x}$

for C to be negative

$\frac{R}{y-1}+\frac{R}{1-x}<0$

$\frac{y-x}{(y-1)(1-n)}<0$

as $y>1$

$\frac{x-1.4}{x-1}<0$

$1<x<1.4$