A thin beam of light enters a thick plastic sheet from air at an angle of $32.0 ^ { \circ }$ with the normal and continues in the sheet at an angle of $23.0 ^ { \circ }$ with the normal. What is the index of refraction of the plastic?

Question

Quizplus · Accepted Answer

Using Snell's Law, $ n_1 \sin(\theta_1) = n_2 \sin(\theta_2) $. Here, $ n_1 = 1 $ for air, $ \theta_1 = 32.0^\circ $, and $ \theta_2 = 23.0^\circ $. Solving for $ n_2 $, the index of refraction of the plastic, gives $ n_2 = \frac{\sin(32.0^\circ)}{\sin(23.0^\circ)} \approx 1.36 $.

A Thin Beam of Light Enters a Thick Plastic Sheet 32.0∘32.0 ^ { \circ }32.0∘

A Thin Beam of Light Enters a Thick Plastic Sheet $32.0 ^ { \circ }$