Question

The velocity of sound in hydrogen in 1224 m/s. Its velocity in a mixture of hydrogen and oxygen containing 4 parts by volume of hydrogen and 1 part oxygen is

• A. 1224 m/s
• B. 612 m/s
• C. 2448 m/s
• D. 306 m/s

Answer 1

Answer: (B)

612 m/s

Velocity of sound in a medium inversely varies with the square root of density of medium, that is, $v\propto \frac{1}{\sqrt{\rho }}$.

Density of the hydrogen and oxygen mixture $={\rho }_{mix}=\frac{\left(4\right)\left(2\right)+\left(1\right)\left(32\right)}{4+1}=8$

Density of hydrogen $={\rho }_H=2$

$⟹v_{mix}=v_H\sqrt{\frac{{\rho }_H}{{\rho }_{mix}}}=\frac{v_H}{2}=612m/s$