Question

The shape of the sound board kept behind the speaker on the stage of a big hall is.

• A. concave
• B. convex
• C. plain
• D. uneven

Answer 1

The correct option is A concave

Answer is A.
The sound board is a concave board which is placed behind the speaker in large halls or auditoriums so that his speech can be easily heard even by the persons sitting at a considerable distance. The sound board works as follows. The speaker is made to stand at the focus of the concave soundboard. The concave surface of the sound board reflects the sound waves of the speaker towards the audience and hence prevents the spreading of sound in various directions. Due to this, sound is distributed uniformly throughout the hall and even the persons sitting at the back of the hall can hear the speech easily.