Question

. A girl claps and hears the echo after reflection from a cliff which is 1320 meter away from her. If the velocity of sound is 330 m/s, calculate the time taken for hearing the echo.

Answer 1

Given,

A girl claps and hears the echo after reflection from a cliff which is 1320 m away from her.

To Find,

The time taken for hearing the echo if the velocity of sound is 330 m/s.

Solution,

Velocity of sound, v = 330 m/s

Distance from the cliff to where the girl is standing, s = 1320 m

Time taken, t = ?

We know that:

$\mathtt{Speed=\dfrac{Distance}{Time}}$

Therefore,

$\mathtt{Time=\dfrac{Distance}{Speed}}$

Substituting the values,

$\mathtt{Time=\dfrac{1320}{330}}$

= 4 seconds

∴ The girl hears her echo from the reflection from the cliff after 4 seconds.

Knowledge Bytes:

→ Sound is a form of mechanical energy that produces the sensation to hear.

→ Sound travels in waves.

→ The travelling of sound is known as propagation of sound.

→ 330 m/s is the speed in which sound travels in solid.