Question

Explain giving scientific reasons.

a. The roof of a movie theatre and a conference hall is curved.

b. The intensity of reverberation is higher in a closed and empty house.

c. We cannot hear the echo produced in a classroom.

Answer 1

a. The roof of a movie theatre and a conference hall is curved so that the sound after reflection from the ceiling reaches all the parts of the hall uniformly.

b. In an empty house, there is no sound absorbers present such as furnitures, curtains etc. Also, if the room is closed, the sound cannot escape the room. Thus, the sound goes through multiple reflections from the rigid walls of a closed and empty room without the reflections of the sound being absorbed. Hence, the intensity of reflections do not fade which would have faded if the room was not empty (has sound absorbers). Due to this the intensity of reverberation is higher in a closed and empty room.

c. The classrooms are designed in such a way that the distance between the walls are less than 17.2 m. Due to this, the reflections of sound from to walls or echos reach our ears before 0.1 s. Because of this, we are not able to distinguish between the original sound and the echo produced in the classroom.