Question

Give two condition for echo to be heard.

Answer 1

1. Distance between obstacle and source of sound must be at least 17.2m

2. Time interval between the original sound and the reflected one must be at least 0.1 sec.

Answer 2

The two most important conditions for echo to be heard are:::

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

2. The reflected sound must be heard at least after 0.1 second after the original sound has ceased...

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