Question

An echo returned in $3s$. What is the distance of the reflecting surface from the source, given that the speed of sound is $342m/s$?

Answer 1

Given data:

• In the question, it is given that the speed of sound is $342m/s$ and the echo returned back to the source in $3s$.
• So, $V=342m/s$ and $t=3s$
• Assume that, the distance between the reflecting surface and the source is $d$.

Concept used:

• A sound is said to be an echo when the sound is reflected by a surface and reflected back to the source that generated that sound.
• So, according to the question, the echo travels $2d$ distance in $3s$ with the speed of $342m/s$.

Find the required distance:

Therefore,

$$\begin{gathered} 2d=v\times t=342\times 3 \\ \Rightarrow 2d=1026 \\ \Rightarrow d=523 \end{gathered}$$

Thus, the distance of the reflecting surface from the source is $523m$.