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a) Unpolarized light is incident on the surface of diamond (n = 2.4). Some of the light is reflected from the diamond; the rest penetrates the diamond surface and is refracted. Find the angle at which the reflected light is completely polarized and indicate the direction of polarization on a suitable figure.

b) Diamond is interesting for another reason. It ``traps light'' and reflects it internally many times as it bounces from facet to facet. Explain how a diamond (with n = 2.4) traps more light more than a piece of glass (n = 1.5). Your answer should be at least partly quantitative.