Question

what is the minimum distance needed for echo??​

Answer 1

Answer:

$\huge \fbox \pink{Answer}$

Explanation:

17 meters

So this means that the minimum distance the obstacle needs to be at to hear an echo is 17 meters.

So if the obstacles are closer than 17 meters, we won't hear the echo

Answer 2

the minimum distance the obstacle needs to be at to hear an echo is 17 meters.