Scientific

Refractive Index

Definition

The refractive index (n) of a medium is the ratio of the speed of light in a vacuum (c) to its speed in that medium: n = c/v.

Explanation

Vacuum has n = 1 by definition; water is approximately 1.33, meaning light travels 33% slower in water than in vacuum. Diamond's high index of 2.42 causes the dramatic bending and internal reflection that gives cut diamonds their brilliance. Optical fiber uses the refractive index difference between core and cladding to confine light by total internal reflection.

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