Question

A given mass of a gas is allowed to expand freely until its volume becomes double. If $C_{b}$ and $C_{a}$ are the velocities of sound in this gas before and after expansion respectively, then $C_{a}$ is equal to

• A. $2C_{b}$
• B. $\sqrt{2}C_{b}$
• C. $C_{b}$
• D. $\frac{1}{\sqrt{2}}C_{b}$

Answer 1

Answer: (C)

$C_{b}$

Answer 2

For ideal gas, on free expansion there is no change in temperature. Hence $C_{a} = C_{b}$