Chapter 35, Problem 86P

GO In Fig. 35-51a, the waves along rays 1 and 2 are initially in phase, with the same wavelength λ in air. Ray 2 goes through a material with length L and index of refraction n. The rays are then reflected by mirrors to a common point P on a screen. Suppose that we can vary n from n = 1.0 to n = 2.5. Suppose also that, from n = 1.0 to n = n_s = 1.5, the intensity I of the light at point P varies with n as given in Fig. 35-51b. At what values of n greater than 1.4 is intensity I (a) maximum and (b) zero? (c) What multiple of λ gives the phase difference between the rays at point P when n = 2.0?

Figure 35-51 Problems 86 and 87.