Walker, Halliday & Resnick — Interference: Problem 38

38 In Fig. 35-28a, a beam of light in material 1 is incident on a boundary at an angle of \(30^\circ\). The extent to which the light is bent due to refraction depends, in part, on the index of refraction \(n_2\) of material 2. Figure 35-28b gives the angle of refraction \(\theta_2\) versus \(n_2\) for a range of possible \(n_2\) values, from \(n_a = 1.40\) to \(n_b = 2.00\). What is the speed of light in material 1?