In Figure a, the waves along rays 1 and 2 are initially in phase, with the same wavelength in air. Ray 2 goes through

In Figure a, 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 Figure b. 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?

Screen Ray 2n Ray 1 ns 2