question_answer 13)

An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 ms-1  ?

Answer:

Here, speed of sound, v = 342 m/s   Time taken by echo to return, t = 3 s If d is the distance between the source and the reflecting surface, distance covered by sound in time t = d + d = 2d (distance d while going to the reflecting surface and distance d while returning back) As    distance = speed (of sound) x time, or                 2d = 342 (m/s) x 3 (s) = 1026 m  or              d = 513 m