Question

state 2 conditions for echo to be heard .
explain

Answer 1

The conditions are 1)there should be a hard sound reflecting surface and a sound shall be produced and2) the reflecting surface should be more than 17 meters away from the source of sound

Answer 2

the conditions to hear an echo are:
1. there must be a time gap of 0.1 second between the original and reflected sound .
2. distance between source of sound and the obstacle must be 17.2m
hope it helps....