Index of refraction?

Question

A light ray is traveling in a diamond (n = 2.419). If the ray approaches the diamond-air interface, what is the minimum angle of incidence that will result in all of the light being reflected back into the diamond? The index of refraction for air is 1.000.

Answer 1

You will more likely get an answer to this question by listing it in the "Physics" section of Y/A.  It is a fairly straight forward optics question, but not many geologists are well schooled in that area of specialization.  The fact that you state the light is traveling in a diamond is the only link to the Geology section of Y/A (and the medium is irrelevant to the calculation of the angle needed for total internal reflection - the only thing that matters are the relative indices of refraction).