Question

why the speed of light changes when light undergoes refraction

Answer 1

Answer:

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A beam of light is made up of tiny waves. When a beam of light consisting of light waves and travelling in a certain medium falls obliquely ( at an angle ) on the boundary of another medium, then one part of the light waves enters into the other medium first and its speed changes first but the rest of waves enter the other medium a little later and hence its speed changes a little later. The fact that the speed of light waves on one side of a beam of light changes a little before the change in speed of light waves on its other side, causes a change in the direction of light, which is called refraction of light.

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