Thermodynamics Question 7
Question 7 - 25 January - Shift 2
According to law of equipartition of energy the molar specific heat of a diatomic gas at constant volume where the molecule has one additional vibrational mode is :-
(1) $\frac{9}{2} R$
(2) $\frac{5}{2} R$
(3) $\frac{3}{2} R$
(4) $\frac{7}{2} R$
Show Answer
Answer: (4)
Solution:
Formula: Maxwell’s Law Of Equipartition Of Energy, Degree of freedom
Diatomic gas molecules have three translational degree of freedom, two rotational degree of freedom & it is given that it has one vibrational mode so there are two additional degree of freedom corresponding to one vibrational mode, so total degree of freedom $=7$
$C_v=\frac{f R}{2}=\frac{7 R}{2}$
