Question

The speed of sound in hydrogen at STP is $V.$ The Speed of sound in a mixture containing 3 parts of hydrogen and 2 parts of oxygen by volume at STP is $V\sqrt{x}$ then $x$ is

• A. 7
• B. 9
• C. 13
• D. 10

Answer 1

The correct option is A 7

${\rho }_{mix}=\frac{3}{5}.2\rho +\frac{2}{5}\times 32\rho =14\rho$

where density $\rho of{H}_2=2\rho$

density of $O_2=32\rho$

Also, $V\propto \frac{1}{\sqrt{\rho }}$

$\frac{V^{\prime \prime }}{V}=\sqrt{\frac{2\rho }{14\rho }}=\frac{1}{\sqrt{7}}$

$V^{\prime \prime }=\frac{1}{\sqrt{7}}V$