What is the minimum distance required to hear an echo, when the speed of sound in air is `340 ms^(-1)` ?

What is the minimum distance (in metres ) required to hear an echo ?

The minimum distance to hear an echo is (Taking the velocity of sound in air to be 330 m s^(-1) )

What is the minimum distance between the reflector and the listener to hear the echo, when the speed of sound in air is 330 ms^(-1) ?

The minimum distance to hear echo (speed of sound in air is 340 m//s )

An echo of sound produced by a person, is heard from a distant tower after an interval of 1.5 s. If the speed of sound in air is 330 ms^(-1) , then the distance of the tower from the person is _______ m.

A tuning fork of frequency 340 Hz is vibrated just above the tube of 120 cm height. Water is poured slowly in the tube. What is the minimum height of water necessary for the resonance? (speed of sound in the air = 340m/s)

What is the minimum distance of the obstacle from the source of sound for hearing distinct echo ?

A train, standing at the outer signal of a railway station blows a whistle of frequency 400Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10ms^(-1) , (b) receds fromk the platform with a speed of 10ms^(-1) ? (ii) What is the speed of sound in each case ? The speed of sound in still air can be taken as 340ms^(-1)