Answer:
It occurs when a gas passes through a tiny hole.
Explanation:
Effusion is a term used to describe when a gaseous molecule in a container passes or escapes through a tiny/small hole. Effusion and diffusion are two properties of gases that are often used interchangeably, however, they differ.
Effusion differs from diffusion in the sense that the gas passes through a TINY HOLE that is smaller than the normal path. This is contrary to when gas disperses throughout a container as in diffusion.
