11.8 Refractive Index

Refractive Index

A number that measures how much a light ray bends—or refracts—when passing from one transparent medium to another

Equation of Refractive Index

n = c / v

Where n = Refractive index of the material, c = the speed of light (3.0×10⁸), and v = the velocity of light in the new medium

Snell’s Law

n1sin01=n2sin02

Where n = Refractive index of the material, and 0 = the angle of incidence

Light enters a material with a higher refractive index, n₂>n₁

Speed decreases and the ray bends towards the normal

Light enters a material with a lower refractive index, n₁>n₂

Speed increases and the ray bends away from the normal