일반물리학 2 — Interference: Problem 42

42 In Fig. 35-29, a light ray is incident at angle \(\theta_1 = 55^\circ\) on a series of five transparent layers with parallel boundaries. For layers 1 and 3, \(L_1 = 20~\mu\text{m}\), \(L_3 = 25~\mu\text{m}\), \(n_1 = 1.6\), and \(n_3 = 1.45\). (a) At what angle does the light emerge back into air at the right? (b) How much time does the light take to travel through layer 3?