The phenomenon of deviation of light rays from their original path, when they pass from one medium to another, is called ______.

refraction

The correct answer is option 2. refraction.

The phenomenon of deviation of light rays from their original path when they pass from one medium to another is called Refraction.

Refraction is the bending of light rays as they pass from one medium to another with a different optical density. This bending occurs due to the change in the speed of light when it travels from one medium to another. Refraction is responsible for various optical phenomena, such as the bending of a pencil in water, the formation of rainbows, and the action of lenses in focusing light.