- #1

betaleonis

- 8

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## Homework Statement

A ray of light incident on a glass sphere (refractive index sqrt 3) suffers total internal reflection before emerging out exactly parallel to the incident ray. What was the angle of incidence?

μ = refractive index of the glass sphere, i = angle of incidence, r = angle of refraction

## Homework Equations

μ = sin i/sinr

## The Attempt at a Solution

From the figure, it turns out that < AOE = i (since L1 is parallel to L2, the corresponding angles are equal)

i = 2r, which implies that sin i/ sinr = μ, or 2cosr = μ, or r = 30° and i = 60°, which is the answer.

I do not understand why < ABO = r. Why is it so? It'd be helpful if I someone could come up with a different way of approaching the problem.