Question

At 20°C, the minimum distance of a person from a sound reflecting surface to hear an echo is :
(a) 12.2 m
(b) 17.2 m
(c) 15.2 m
(d) 34.4 m

Answer 1

At room temperature, the minimum distance for echo is 17.2 m.
Ans: (b) 17.2 m.