일반물리학 2 — Interference: Problem 54

54 In Fig. 35-30, a light wave along ray \(r_1\) reflects once from a mirror and a light wave along ray \(r_2\) reflects twice from that same mirror and once from a tiny mirror at distance \(L\) from the bigger mirror. (Neglect the slight tilt of the rays.) The waves have wavelength \(\lambda\) and are initially exactly out of phase. What are the (a) smallest, (b) second smallest, and (c) fourth smallest values of \(L/\lambda\) that result in the final waves being exactly in phase?