Question

Give the conditions for an production of Echo? Why do we not get echo in small rooms?

Answer 1

Hint: An echo can only be heard if it falls under some necessary conditions. If any of these conditions fail to be met, the echo would not be heard. To answer this question, the condition of the object to be placed at a certain distance from the sound source should be considered.

Complete Step-by-Step solution:
An echo is the sound heard after the reflection of the original sound from a distant object. For an echo to be produced the following conditions are required:
1. The minimum distance between the source sound and the reflecting object should be 17.2 meters.
2. The time difference between source and reflector should be minimum 0.1 seconds.
3. The reflecting object or body should be of large area as compared to the wavelength of sound. Larger and more rigid objects tend to produce louder echoes.
4. The intensity or loudness of the source sound should be sufficient enough to be heard as an echo.
We do not hear echo in a small room because the distance between our mouth and the walls of the room is smaller than 17.2 meters. Since the first condition for the production of echo is not satisfied, we do not hear the echo.

Note: The distance required for the production of echo is different for different mediums. As the speed of sound is different in varying mediums, the distance also varies accordingly. For instance, if the speed of sound in seawater is 1400 m/s, the minimum distance for echo to be heard will be 70 meters.