Question

Which of the following shows Brownian motion?

• A. The motion of dust particles in a ray of sunlight
• B. The motion of ants in a colony
• C. The motion of apple when falling from a tree
• D. The motion of kites in the sky

Answer 1

The correct option is A

The motion of dust particles in a ray of sunlight

The motion of dust particles in a ray of sunlight is an example for Brownian motion. The particles in the ray of sunlight move in a zig-zag manner due to the intermixing of dust particles which are in continous motion with the particles of air. Rest other examples don't have particles in constant motion in a zig-zag manner.