Question

A person places his ear at the end of a long steel pipe. He hears two distinct sounds at an interval of 0.5 s when another person hammers at the other end of the pipe. If the speed of the sound in metal and air are 3630 m$s^{-1}$ and 330 m$s^{-1}$ respectively, then the distance between the two persons is

• A. 90.75 m
• B. 181.5 m
• C. 363 m
• D. 1650 m

Answer 1

The correct option is B 181.5 m

$l=V_{air}\times t+0.5=V_{steel}\times t$

$t=\frac{V_{air}\times 0.5}{(V_{steel}-V_{air})}$

$t=\frac{330\times 0.5}{3630-330}=\frac{330\times 0.5}{3300}=0.05sec$

$l=V_{steel}\times t=3630\times 0.05=181.5m$