Question

An echo is not heard in a small room.why ? give reason
​

Answer 1

The room is too small it has to be ag least 17.2 meters for the noise to bounce

Answer 2

They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the room should be 17.2 m.

hopw it helps