Final answer:
Refraction of light occurs due to the change in speed of light when it crosses the boundary between two media, causing the light to bend or change direction.
Step-by-step explanation:
The refraction of light as it passes between two media is caused by the change in the speed of light when it crosses the boundary between the two media. This speed change leads to a change in the direction of light, which we observe as refraction.
Refraction occurs because light travels at different speeds in different mediums. When light enters a medium with a different optical density, such as going from air to water or from air to glass, its speed changes. This change in speed causes the light to bend or change direction.
For example, when light travels from air to water, it slows down and bends towards the normal, which is a line perpendicular to the surface of the water. When light travels from water to air, it speeds up and bends away from the normal.
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