What is Refraction? Definition, Meaning & Example
The bending of light as it passes from one medium to another medium with a different optical density.
TL;DR: The bending of light as it passes from one medium to another medium with a different optical density.
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Refraction: The bending of light as it passes from one medium to another medium with a different optical density.
Explanation
Refraction occurs because light travels at different speeds in different materials. When light enters a denser medium like glass or water, it slows down and bends toward the normal line. When light enters a less dense medium, it speeds up and bends away from the normal. The amount of bending depends on the refractive indices of the two materials. Refraction explains why objects underwater appear closer than they actually are, why lenses work, and why rainbows form.
Example
A stick appears bent at the point where it enters water because light from the submerged part refracts as it travels from water to air, changing its direction before reaching your eye.
Frequently Asked Questions
What is the normal line in refraction?
The normal is an imaginary line perpendicular to the surface where light enters the new medium. The angle of incidence and refraction are measured from this normal.
Why do lenses use refraction?
Lenses bend light at curved surfaces; converging lenses focus light rays to a point, while diverging lenses spread them apart, useful for glasses and cameras.
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