(i) Which property of sound leads to the formation of echoes? Briefly explain.
(ii) What will happen, if the reverberation time in a big hall is too long?
(i) The property which leads to the formation of echoes is reflection of sound. When a sound is repeatedly reflected and if minimum distance between sound sources and reflecting surface is more than 17.2 m, then we hear echoes.
(ii) If the reverberation time in a big hall is too long, then sound becomes distorted, blurred and confusing.