Question

State two conditions necessary for an echo to be heard distinctly?

Answer 1

1. an echo can be heard when the sound strike with hard reflecting surface
2. the distance between listener and striking surface should be upto 17 metre
hope it helps you
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Answer 2

Hey mate

Here is your answer

The first condition is the minimum distance between source and reflecting surface should be 17.2m.

2-to hear a distinct echo, the interval between original and reflected sound 0.1 second.

Hope it helps!