Question

An echo returns in $3s$. What is the distance of the reflecting surface from the source?

• A. $1020m$
• B. $22.66m$
• C. $510m$
• D. $2.28m$

Answer 1

Answer: (C)

$510m$

Time taken by sound to travel from the source to the deflecting surface $t=\frac{3}{2}=1.5s$

Speed of sound $v=340m/s$

So, distance between the surface and the source $=v\times t=340\times 1.5=510m$