Question

If the ceiling of a cinema is made flat, what will happen?
(A) No sound will be audible at all
(B) Picture will vanish
(C) Sound will not reach properly to every person
(D) Picture will not be clear to everyone

Answer 1

Hint Sound waves follow the laws of reflection just like light waves so because of reflection, the sound waves reach everywhere in the cinema.

Complete step-by-step solution
Since sound waves are longitudinal waves they undergo reflection, refraction and many other phenomena under proper conditions. The same phenomena involved in cinema halls as well.

The ceiling of cinema halls are usually made curved or in a dome shape like structure because of this structure the sound waves undergo reflection and they reach every corner of the hall which in turn makes it audible for every person in the hall. Unlike this if the ceiling is made flat the sound waves do not reach some places or to every corner hence it will not reach every person.

Therefore, the correct option is C.

Note: Reflection of sound waves takes place in echos, roaring of thunder, reverberation in halls etc. These are some daily life examples. They also play an important role in speaking tubes, horns, trumpets, sound boards etc.