Sound — Question 6

As we know,

$\text {Speed of sound (V)} = \dfrac{\text{Total distance travelled (2d)}}{\text {time interval (t)}} \\[0.5em]$

Total distance travelled by the sound in going and then coming back = 2d

Given,

d = 48 m

V = 320 ms^-1

Substituting the values in the formula above, we get,

$320 = \dfrac{2 \times 48}{t} \\[0.5em] t = \dfrac{2 \times 48}{320} \\[0.5em] t = 0.30 s \\[0.5em]$

Hence, time after which echo is heard = 0.30 s.