Question

What is an echo? What is the condition in order to hear an echo.

Answer 1

Echo:

1. An echo is basically a reflection of a sound wave. When a sound wave gets reflected by a hard surface and comes back to the listener with a little delay.
2. Then the reflected sound heard by the listener is known as the echo of the original sound wave.
3. An echo is formed when a sound wave reflects back towards its source after reflecting from a hard surface.

The condition necessary to hear an echo:

1. To hear a distinct echo, the time interval between the original sound and the reflected one must be at least 0.1 s.
2. For hearing distinct echoes, the minimum distance of the obstacle from the source of sound must be 17.2 m.
3. Echo is a repetition of sound due to the reflection of original sound by a broad and hard obstacle.