question_answer

  A child hears an echo from a cliff, 4s after the sound from a powerful cracker is produced. How far away is the cliff from the child? [Take velocity of the sound in air as 330 m/s]

Answer:

                                    The time taken by echo to be heard,  ( In case of echo, sound covers twice the distance between sound source and reflector) Velocity of sound in air = 330 m/s or