Question

Sawdust is added to gypsum used in making plaster slab to ___________

(a) Increase its weight

(b) Reduce its weight

(c) Impart colour

(d) Impart odour

I have been asked this question by my college director while I was bunking the class.

My doubt stems from Types of Partitions in division Cavity Walls & Partition Walls of Construction & Building Materials

Answer 1

Right answer is (b) Reduce its weight

The best explanation: Sawdust is added to gypsum used in making plaster slab in order to reduce its weight. Instead of sawdust, other fibrous material may be used. Plaster slabs are good insulators of heat and sound.