Kinetic Theory - Result Question 23

23. The value of $\gamma=(\frac{C_p}{C_v})$, for hydrogen, helium and another ideal diatomic gas $X$ (whose molecules are not rigid but have an additional vibrational mode), are respectively equal to,

[NEET Odisha 2019]

(a) $\frac{7}{5}, \frac{5}{3}, \frac{7}{5}$

(b) $\frac{7}{5}, \frac{5}{3}, \frac{9}{7}$

(c) $\frac{5}{3}, \frac{7}{5}, \frac{9}{7}$

(d) $\frac{5}{3}, \frac{7}{5}, \frac{7}{5}$

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Answer:

Correct Answer: 23. (b)

Solution:

  1. (b) For Hydrogen $f=5$

For Helium $f=3$

For gas $X$

$f=7$.

$\gamma=1+\frac{2}{f}=1+\frac{2}{7}=\frac{9}{7}$

So, $(\frac{7}{5}, \frac{5}{3}, \frac{9}{7})$