Question

The relation between U,P and V for an ideal gas is $U=2+3PV$. the gas is

• A. Monoatomic
• B. Diatomic
• C. Polyatomic
• D. Either a Monoatomic or Diatomic

Answer 1

The correct option is C Polyatomic

Given:

U = 2+ 3PV

$\Rightarrow U=2+3nRT$

Differentiating with respect to T,

$\Rightarrow \frac{dU}{dT}=0+3nR\frac{dT}{dT}$

$\Rightarrow C_v=3nR$

For 1 mole of a gas, n=1

$\Rightarrow C_v=3R$

Since the specific heat at constant volume is 3R for triatomic gas in which atoms are non linear,

Therefore, correct option is C( polyatomic).