Question

A boy standing in front of a wall at a distance of 85m produces 2 claps per second. He notices that the sound of his clapping coincides with the echo. The echo is heard only once when the clapping is stopped calculate the speed of sound.​

Answer 1

Given:–

• Distance (d) = 85m

• Number of claps per second = 2 claps

To find:–

• Speed of sound

Concept:–

• Speed of sound by echo method

Understanding the concept...

The echo method can be used to determine the speed of sound in air. For this, sound is produced from a place at a known distance say, d at least 50 m from the reflecting surface. The time interval t in which the echo reaches the place from where the sound was produced, is noted by a stop watch having the least count 0.001 s. Then the speed of sound is calculated by the following relation:

$\bold\pink{ \dfrac{total \: distance \: travelled}{time \: interval}}$

It is repeated several times and then the average value of speed of sound V is determined.

Step by step explaination:–

Calculating the total distance...

That is,

→ 2d

→ 2 × 85

→ 170 m

As 2 claps are produced in one second.

So, in order to find time.

→ time taken = 1/2

→ 0.5 s

Calculating the speed of sound...

That is,

$\dfrac{170}{0.5}$

$340ms {}^{ - 1}$