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 × ...