Question

What is the minimal condition for the echo to be produced?​

Answer 1

Answer:

Sound absorbing material must not be present.

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 .

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