Question

Define Echo. Also calculate the minimum distance required to hear an echo when at a place speed of sound is 1260m/s and minimum time to hear echo is 0.1 sec.

Answer 1

So the minimum distance required to hear an echo in air is achieved by: d=343*0.05 or, d=17.15 Therefore to hear echo in air at room temperature, the minimum distance is 17.15m.