Question

The value of $\gamma\left(=\frac{C_{p}}{C_{y}}\right)$ , for hydrogen, helium and another ideal diatomic gas $X$ (whose molecules are not rigid but have an additional vibrational mode), are respectively equal to :

• A. $\frac{7 }{5 }, \frac{ 5}{ 3}, \frac{ 9}{7 }$
• B. $\frac{ 5}{ 3}, \frac{ 7}{ 5}, \frac{ 9}{7 }$
• C. $\frac{5 }{ 3}, \frac{ 7}{ 5}, \frac{ 7}{5 }$
• D. $\frac{7 }{5 }, \frac{5 }{3 }, \frac{7 }{5 }$

Answer 1

Answer: (A)

$\frac{7 }{5 }, \frac{ 5}{ 3}, \frac{ 9}{7 }$

Answer 2

Hydrogen $\to 7/5$ (diatomic),
Helium $\to 5/3$ (monoatomic),
$X \to 9/7$