Final answer:
Refraction is the bending of light as it passes from one medium to another with a different optical density.
Step-by-step explanation:
The bending of light is called refraction.
Refraction occurs when light passes from one medium into another medium with a different optical density, causing the light to change direction. This change in direction is due to the change in speed of light as it travels through different materials.
For example, when light passes from air into water, it bends towards the normal line because the speed of light is slower in water than in air.
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