Question

the minimum time requrird for producing an echo is​

Answer 1

Answer:

Answer: The velocity of sound in dry air is approximately 343 m/s at a temperature of 25 °C. Therefore, the reflecting object must be more than 17.2m from the sound source for echo to be perceived by a person located at the source

Answer 2

Answer:

To hear an echo, the time difference should be a minimum of 0.1 second. Speed of sound at 20 degree C is 343 m/s . Distance that sound travels in 0.1 s is 34.3 m . If the time is less than 0.1 s , the first sound being still in memory , we hear a prolonged sound called reverberation sound.