Question

A boy standing in front of a wall at 17 m produces 10 claps per second. He notice that the sound of his clapping coincides with the echo. Echo is heard only once when clapping is stopped. Calculate the speed of sound :

• A. 340 m/s
• B. 360 m/s
• C. 290 m/s
• D. 300 m/s

Answer 1

The correct option is A 340 m/s

In the question, it is given that the distance traveled by sound is $2\times 17=34m$ as it is a reflected or echo sound. The frequency of the clap is 10 Hz. We know that time taken is the inverse of frequency.
Hence, the time taken is calculated as follows.
$T=\frac{1}{f}=\frac{1}{10}=0.1seconds.$
The velocity or speed of the sound is calculated from the relationship as follows.
$Speedofsoundv=\frac{Distancetraveledm}{Timetakens}$
That is,$v=\frac{34m}{0.1s}=340m/s$.
Hence, the speed of the sound is 340 m/s.