Kinetic Theory Of Gases Question 99
Question: One mole of a diatomic gas is taken through the process $ PV^{n}=k, $ where n and k are constant. If the heat capacity of gas is negative, then the value of n may be
Options:
A) $ \frac{5}{7} $
B) $ -\frac{5}{7} $
C) $ \frac{9}{7} $
D) $ -\frac{9}{7} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ C=\frac{R}{\gamma -1}+\frac{R}{1-n} $ for a polytropic process
$ \Rightarrow C=\frac{5R}{2}+\frac{R}{1-n}\text{ }( \
Therefore r=\frac{7}{5}\text{ for a doatomic gas} ) $ For C to be negative, the possible value of 9 n will be $ \frac{9}{7}. $