The illustration shows total internal reflection taking place in a piece of glass. The index of refraction of this glass:

Question

Quizplus · Accepted Answer

Total internal reflection occurs when the angle of incidence is greater than the critical angle, which is given by $	heta_c = \sin^{-1}(\frac{1}{n})$, where $n$ is the index of refraction of the medium. In this case, since total internal reflection is occurring, we know that the angle of incidence is greater than the critical angle, which means that $\sin^{-1}(\frac{1}{n}) < 1$. Solving for $n$, we get $n > \frac{1}{\sin(1)} \approx 1.15$. Therefore, the index of refraction of the glass is at least 1.15, and the best choice is C.

The Illustration Shows Total Internal Reflection Taking Place in a Piece