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In a prism, violet light undergoes more refraction than light of higher wavelength. Is there any explanation as to why light of higher frequencies refract more than light of lower frequencies?

Paddy
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    Yes there is. But it takes the best part of a year in a upper-division E&M class to develop the formalism to show it. How is your vector calculus and differential equations? Without that it comes down to someone telling you that various optical parameters are functions of frequency and this is how the dependence goes. – dmckee --- ex-moderator kitten May 08 '16 at 04:26
  • Feynman explains the introduction to this phenomenon nicely: http://www.feynmanlectures.caltech.edu/I_31.html – GodotMisogi May 08 '16 at 05:06
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    Possible duplicate of http://physics.stackexchange.com/q/65812/ – UKH May 08 '16 at 07:12
  • @dmckee---ex-moderatorkitten, 4 years after asking this question, I am halfway through Griffiths' E&M (self-study though) and beginning to understand what this is leading to. – Paddy May 31 '20 at 01:09

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One way to look at this is to go to the definition of the index of refraction $$n = \frac{c}{v}$$ v is related to the wavelength and frequency as $$v = \lambda f$$ So the index of refraction becomes $$n = \frac{c}{\lambda f}$$ Frequency remains the same when light goes into a new medium, so the only difference between light of different colors is the wavelength. The lower wavelength of violet light will give a greater value for n, and so light will be refracted more.

Community
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Edmund Witkowski
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  • I find it interesting that you emphasize (correctly) that frequency is the property of the light waves that remains the same on transitions through material media, but also write the dispersion in the wavelength-dependent form. From the raw math of Maxwell's Equation it is clear that the frequency is the proper independent variable, but we have this long running historical tendency to write it in terms of wavelength (and then insist "vacuum wavelength!" to overcome the silliness that would otherwise ensue). Any way, thus endeth my rant. – dmckee --- ex-moderator kitten May 08 '16 at 17:28