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Different frequencies of light travel at different speeds through solids, which along with Snell's law allows for rainbows. Has this phenomenon of variable speeds been predicted through derivations? What does it tell us about the interactions that occur when light travels through a solid?

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Read/learn a lot about condensed matter physics, then ask again. – Georg Oct 17 '11 at 9:00
Obviously this phenomenon has first been observed, and then (after centuries) explained. BTW it was first observed incorrectly (by the Newton's corpuscular theory of light). There exist two explanations: classical and quantum. You should read about them – valdo Oct 17 '11 at 9:48
@Georg: I think it's a reasonable question. If it can't be answered without going off and becoming an expert, that's another matter. – Mike Dunlavey Oct 17 '11 at 14:08
@Georg Is there a particular book or website that you would recommend? – Dale Oct 17 '11 at 23:18
up vote 2 down vote accepted

The index of refraction is found to be a function of the frequency in an analysis of radiation scattering in a medium: for example in the book of Panofsky and Philips "classical electricity and magnetism" chapter 22, radiation scattering and dispersion ,on paragraph 7. The book seems to be available for a free download here.

Here is a link with Feynman lectures on light to to get the extended framework on light.

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