What is an echo? When can we distinctly hear the echo of a sharp sound? Why cannot we hear an echo in a small halls ?
Q. What is an echo? When can we distinctly hear the echo of a sharp sound? Why cannot we hear an echo in a small halls ?
Ans. An echo is the phenomenon of repetition of sound of a source by reflection from an obstacle. For hearing an echo, the obstacle must be situated at a suitable distance from the source. Due to persistence of hearing the sound must take at least 1/10th of a second in reaching the listener. If d is the minimum distance of the reflecting object from the source, then time t taken to cover the distance 2d must be 1/10th second.
Therefore, t = 2d/V or d = Vxt/2 = 340 × 1/20 = 17 m.
Echoes are not heard in a small room because the distance is less than the minimum distance of 17 m required for hearing the echo distinctly.
Follow on Facebook page – Click Here
Google News join in – Click Here
Read More Asia News – Click Here
Read More Sports News – Click Here
Read More Crypto News – Click Here