Question

write essential condition for hearing an Echo

Answer 1

The echo is a repetition of sound produced due to its reflection , It can be used to tell how far away an object is , how fast the object is moving , and even its shape .

If you make a sound in a large empty room , you will hear a repetition of your sound , Also if you visit a large empty place containing hard flat surfaces  and produce a sound , you will hear a repetition of your sound .

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 .