Suppose that the two waves in Figure have wavelength = 500 nm in air. What multiple of gives their phase difference when they

Suppose that the two waves in Figure have wavelength λ = 500 nm in air. What multiple of λ gives their phase difference when they emerge if

(a) n1 = 1.50, n2 = 1.60, and L = 8.50μm;

(b) n1 = 1.62, n2 = 1.72, and L = 8.50μm; and

(c) n1 = 1.59, n2 = 1.79, and L = 3.25μm?

(d) Suppose that in each of these three situations the waves arrive at a common point (with the same amplitude) after emerging. Rank the situations according to the brightness the waves produce at the common point.