Question

Ram is standing 165 m behind Shyam. Shyam is standing 'd' meters away from a wall in the same line. Ram claps and Shyam hears the echo of clap after 2 seconds he heard sound of direct clap. Find the value of 'd'. (Assume speed of sound to be $330m{s}^{-1}$)

• A. 165 m
• B. 660 m
• C. 330 m
• D. 82.5 m

Answer 1

The correct option is C

330 m

After hearing the direct clap, sound travels a distance of 'd', hits the wall, gets reflected and reaches Shyam in 2 seconds
Therefore, the total distance travelled in 2 seconds is 2d
We know $speed=\frac{distance}{time}$
Or $distance=speed\times time$
Given speed of sound is $330m{s}^{-1}$
Therefore, distance travelled in 2 seconds is,
Distance $=330\times 2=660m$
$2d=660\Rightarrow d=\frac{660}{2}=330m$