A conical hole in plastered surface is formed due to ___________

a-conical-hole-in-plastered-surface-is-formed-due-to

A conical hole in plastered surface is formed due to ___________
A. Popping
B. Rust stains
C. Softness
D. Uneven surface
Right choice is A. Popping

Sometimes the Plaster mix contains particles with expand on being set. A conical hole in plastered surface is formed in front of the particle. This conical whole is known as the blow or pop.