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I've been having trouble with this for a few days and already used up all my tries on the homework for it, but have the final is coming next week. Thus I would like to know how do this, however I cannot figure out what the right equation is for the slabs dispersion.

A light beam containing red and violet wavelengths is incident on a slab of quartz at an angle of incidence of 61.5°. The index of refraction of quartz is 1.455 at 600 nm (red light), and its index of refraction is 1.468 at 410 nm (violet light). Find the dispersion of the slab, which is defined as the difference in the angles of refraction for the two wavelengths.

Would appreciate any help, thank you.

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How would you calculate the angle after refraction? – Bernhard Apr 21 '12 at 18:31

The problem is probably simpler than you think. The light beam is refracted as it passes through the top of the slab, and you can use Snell's Law to calculate the transmitted angle. You'll find the angle is different for the two wavelengths, and question is asking for this difference.

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