Q.3 The material generally used for soundproofing of rooms like a recording studio and auditorium etc., is

1. cotton

2. )coir

3. wood

4. styrofoam

Ans. (d) The material generally used for soundproofing of rooms like a recording studio, cinema hall, an auditorium that absorbs sound, and facilitates in proofing is styrofoam. Earplugs (a device used by a working person of the commercial and industrial zone) are made up of very fine glass Wood or cottonwood impregnated with wax while ear muffs contain fluid seals or plastic foam for absorbing sound.