Refraction in Physics
Refraction is the bending of light when it passes from one material into another, like from air into water or glass. This happens because light changes speed in different materials.
Why Does Light Bend?
When light enters a denser material (like air to glass), it slows down and bends towards the normal (an imaginary line at 90° to the surface).When light goes into a less dense material (like glass to air), it speeds up and bends away from the normal.
Everyday Examples of Refraction:
A straw looks bent in a glass of water
Lenses in glasses or cameras use refraction to focus light
Rainbows form because of refraction in water droplets
Refraction Index (n):
The refractive index tells us how much a material slows down light.Higher n = more bending.
Everyday Examples of Refraction:
A pencil looks bent in a glass of water.
Lenses in glasses and cameras focus light using refraction.
Diamonds sparkle because of their high refractive index.
Rainbows form when sunlight refracts through water droplets in the air.
Total Internal Reflection:
If light travels from a denser to a less dense material at a steep angle, it can be completely reflected instead of refracted. This is called total internal reflection and is how optical fibres work.