'm currently reading chapter 27 of the Feynman lectures, where he derives the thin lens equation for a single refracting surface. He arrives at the equation(adsbygoogle = window.adsbygoogle || []).push({});

h^2/2s + nh^2/s' = (n-1)h^2/2r

Where s is the object distance, s' is the image distance, n is the index of refraction of the second medium (the first is one), r is the radius of curvature, and h is the altitude of a triangle

Where does the (n-1) come from? Wouldn't it simply be n?

This is kind of vague, so please look at the second page of

http://student.fizika.org/~jsisko/K...on Physics/Vol 1 Ch 27 - Geometric Optics.pdf

I would be so grateful. Thanks.

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# Derivation of the thin lens equation?

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