An echo returned in 3 s. What is the distance of reflecting surface from the source ? Given that the speed of sound is `342 s^ -1`.

Explanation

Speed of sound, V= `342 ms^(-1)`. Time taken for hearing the echo, t=3s
Distance travelled by the sound `V xx t`
`=342 ms^(-1) x 3s = 1026m`
In 3s sound has to travel twice the distance between the reflecting surface and the person. Hence the distance between teh reflecting surface and the person
`=(1026m)/(2)= 513m`