Halliday, Resnick & Walker — Electromagnetic Waves: Problem 54

54 In Fig. 33-48, a light ray in air is incident at angle $\theta_1$ on a block of transparent plastic with an index of refraction of 1.56. The dimensions indicated are $H = 2.00\text{ cm}$ and $W = 3.00\text{ cm}$. The light passes through the block to one of its sides and there undergoes reflection (inside the block) and possibly refraction (out into the air). This is the point of first reflection. The reflected light then passes through the block to another of its sides — a point of second reflection. If $\theta_1 = 40^\circ$, on which side is the point of (a) first reflection and (b) second reflection? If there is refraction at the point of (c) first reflection and (d) second reflection, give the angle of refraction; if not, answer “none.” If $\theta_1 = 75^\circ$, on which side is the point of (e) first reflection and (f) second reflection? If there is refraction at the point of (g) first reflection and (h) second reflection, give the angle of refraction; if not, answer “none.”