Question

What is echo? Under what conditions echo can be heard

Answer 1

The reversion of sound is called echo.

for eacho you must have empty room with Atleast 15 in dimension.

Answer 2

The conditions necessary for hearing the echo:

The conditions necessary for hearing the echo:The distance between the sound source and the reflecting surface must not be less than 17 metres where the time period between hearing the original sound and its echo should not be less than 0.1 of a second .