Question

What is difference between denser and rarer medium? what is the components of these mediums which changes the speed of light?

Answer 1

A medium in which the speed of light is more is known as Optically Rarer medium .
Air is optically rarer medium as compared to glass and water.

A medium in which speed of light is less is known as optically denser medium.
glass is optically denser medium as compared to air.

The refractive index of a medium gives an indication of light bending ability of that medium.
For example:
Refractive index of glass is greater than the refractive index of water . Hence light bends more in glass than in water.
If Refractive index is more bending of light is more and speed of light will be less.

Answer 2

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