Question

answer both in short it is 9th std question friends ​

Answer 1

Explanation:

1. The roof of the movie theater as well as the conference hall are intentionally made curved . This is done so that the sound produced can be reflect from the roof parts and also from the walls so that the sound produced can be reached in all part of the theater or the conference hall.
2. The reverberation time is larger for an empty hall than for a crowded hall because there are many sound absorbers present in a crowded room, whereas the sound is reacted back by the walls of an empty room. Therefore it persists for a longer time in an empty hall.

Answer 2

Answer:

a.to avoid reverberation the roof of a movie theatre and a conference hall is curved.

b.in closed and empty house there are no things which can absorb waves so the intensity of reverberation is higher.

c.the conditions required to produce echo are not be agreed in classroom so we cannot hear echo in classroom.