| Themes > Science > Physics > Optics > Wave Properties of Light > Dispersion | ||||||||||||
The velocity of light in a material, and hence its index of refraction, depends on the wavelength of the light. In general, n varies inversely with wavelength: it is greater for shorter wavelengths. This causes light inside materials to be refracted by different amounts according to the wavelength (or colour). This gives rise to the colours seen through a prism. Rainbows are caused by a combination of dispersion inside the raindrop and total internal reflection of light from the back of raindrops. The following is a chart giving the index of refraction for various wavelengths of light in glass.
Note: In general shorter wavelengths (i.e. light towards the blue end of the spectrum) have higher indices of refraction and get bent more than light with longer wavelengths (towards the red end). |
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