JEE Main20203 Sep 2020Morning ShiftPhysicsKinetic Theory of GasesActual
Consider a gas of triatomic molecules. The molecules are assumed to be triangular and made of massless rigid rods whose vertices are occupied by atoms. The internal energy of a mole of the gas at temperature T is:
Options
- A5 2 R T
- B3 2 R T
- C9 2 R T
- D3 R T
Correct answer
D. 3 R T
Step-by-step solution
The formula of internal energy of a gas is given by U = f 2 RT Here R is the gas constant and T is temperature. R = 8 . 314   J   mol - 1   K - 1 For the given configuration of triatomic molecules, the degree of freedom f = 6 ⇒   U = 6 2 RT = 3 RT