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I have learned that the law of refraction is n = sinI/sinR, where n is the refractive index, I is the angle of incidence, and R is the angle of refraction.

But why is it sinI/sinR, and not simply angle I/angle R if it is identifying the ratio between the two angles?

I have heard that I need to do some trigonometric manipulation but I don't know what this manipulation is. Thanks.

(i.e. if I = 60 degrees, and R = 30 degrees, then the refractive index is sqrt(3), not 2... but why? how was this law derived?)

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# Derivation of Law of Refraction

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