Question

a man is standing at a distance of 12m from a cliff. will he be able to hear an echo of his sound?give reason

Answer 1

No the person cant hear an echo because the minimum distance between the source of sound and the reflecting surface is 17m.
explanation: we can hear two sounds separately if the time gap between these two sounds is more than 1/10 th of a second.
distance=speed*time
344*0.1=34.4m
so echo will be heard if the minimum distance between the source and the obstacle is 34.4/2 =17.2m

Answer 2

heya...☺...
The man would not be able to hear an echo of his sound clearly because for clear echo the distance between the source of echo must be 17 m or more.
hope it works.....☺