Light changes speed as it passes from one medium to another. This is called refraction. The frequency of light does not change as it refracts. The refractive index of a material is a measure of ...

We can also use wavelengths to calculate refractive index. By substituting \(v_{1}=f\lambda _{1}\) and \(v_{2}=f\lambda _{2}\) into \(n=\frac{v_{1}}{v_{2}}\) then ...