What is the refractive index?

1 Answer
Sep 20, 2016

It is a pure number that gives us the value of the ratio between the speed of light in vacuum and the speed of light inside a medium.

Explanation:

In passing from vacuum to a medium light slows down. So if we cal the speed of light in vacuum #c# and in the medim #v#, then the refractive index #n# will be:
#n=c/v#
It is a way to carachterize a phisical medium (say, water) with respect to the change in speed of light it produces so that you'll have different values for different materials:

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