Question

The speed of sound in hydrogen at NTP is $1270 \,ms$ 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)

635 ms

Answer 2

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 $4 \,V$. If $\rho_{m}$ be the density of mixture, then $\rho_{m}=\frac{4 V \times 1+V \times 16}{5 \,V}=4$ As $v \propto\left(\frac{1}{\rho}\right)^{1 / 2}$. $\therefore$ Velocity in mixture $=\frac{1270}{(4)^{1 / 2}}$ $=635 \,m / s$