Question

What is an echo? What factors are
important to get a distinct echo?​

Answer 1

Echo is the sound heard after reflection from a rigid surface such as a cliff, a hillside, the wall of a building etc. ... So from the rigid surface because the sound heard after the reflection.

The repetition of sound caused by its reflection off a hard surface is known as echo. Factors important to get a distinct echo are: The minimum distance between the source and reflector of sound should be 17 m. The size of reflector must be large enough as compared to the wavelength of the sound wave.

Answer 2

echo is imitation (repetetion) of sound

The minimum distance between the source and reflector of sound should be 17 m.

The size of reflector must be large enough as compared to the wavelength of the sound wave.