Question

in a beam of Sunlight entering a room we can some we can sometimes see dust particles moving in haphazard way which phenomena can describe this

Answer 1

Dust particles in air form a colloid. The continuous zig-zag movement of tiny dust particles suspended in air results from their collision by the fast-moving particles of air. This haphazard or random motion of particles is known as Brownian motion.

Answer 2

Dust particles in air form a colloid.The haphazard movement of particles suspended in air is a result of a collision from the fast moving particles of air.