A man is standing at a distance of 12 m from a cliff. Will he be able to hear a clear echo? Give a reason for your answer.
t = 2d/V = 2 × 12/340 = 24/340 < 0.1 seconds so the man will not be able to hear the echo. This is because the sensation of sound persists in our ears for about 0.1 second after the exciting stimulus ceases to act.