Echo

                          🎷   Echo  🎷

⚫ So , What is an Echo ?

You must have visited an echo point at a hill station . If you shout loudly at such a point , you hear the same sound just after a little while . This sound is an echo .

An echo is the repetition of the original sound because of the reflection by some surfaces .

In order to be able to hear the original sound and its reflection distinctly , at 22°C .

⚫ What must the minimum distance be between the source and the reflecting surface ? 

At 22°C , the velocity of sound in air is 344 m/s . Our brain retains a sound for 0.1 s after starting from the source to get reflected and come back to us . 

Thus , we can determine the minimum distance between the source and the reflecting surface .

Distance =  Speed  ×  Time .

                =  344  m/s   ×   0.1 sec

                =  34.4 m .

Thus , to be able to hear a distinct echo , the reflecting surface should be at a minimum distance of half of 34.4 m  that is  17.2 meters .

As , Velocity of sound depends on the temperature of air , this distance depends on temperature .

Echo can be heard multiple times due to continuous or multiple reflections . The golghumat at Vijapur in Karnataka is an excellent example of an Echo ...