Question

Velocity of hydrogen at NTP is V. The velocity of sound in a mixture of hydrogen and oxygen in the ratio of 4:1 at NTP is

• A. $\frac{1}{5}V$
• B. $\frac{1}{4}V$
• C. $\frac{1}{3}V$
• D. $\frac{1}{2}V$

Answer 1

Answer: (D)

$\frac{1}{2}V$

$V=\sqrt{\frac{rKT}{m}}$

$r$ is same for both gases effective mass of gases

$\frac{4}{5}\times 2+\frac{1}{5}\times 32=8$

$V=\sqrt{\frac{rKT}{2}}$

$V_f=\sqrt{\frac{rKT}{8}}$

$V_f=\frac{1}{2}\sqrt{\frac{rKT}{2}}$

$V_f=\frac{1}{2}V$