Question

The speed of sound in hydrogen at NTP is $1270ms$ Then, the speed in a mixture of hydrogen and oxygen in the ratio $4:1$ by volume will be

• A. 317 ms
• B. 635 ms
• C. 830 ms
• D. 950 ms

Answer 1

Answer: (B)

As given, the volumes of hydrogen and oxygen in a mixture is $41$, so let $V$ be the volume of oxygen. The volume of hydrogen will be $4V$.
If ${\rho }_m$ be the density of mixture, then
${\rho }_m=\frac{4V\times 1+V\times 16}{5V}=4$
As $v\propto {\left(\frac{1}{\rho }\right)}^{1/2}$.
$\therefore$ Velocity in mixture $=\frac{1270}{(4{)}^{1/2}}$
$=635m/s$