*67 O In the ray diagram of Fig. 33-63, where the angles are not drawn to scale, the ray is incident at the critical angle on the inter- face between materials 2 and 3. Angle o = 60.0°, and two of the in- dexes of refraction are n = 1.70 and n2 = 1.60. Find (a) index of refraction n3 and (b) angle 0. (c) If øi decreased, does light refract into material 3? Figure 33-63 Problem 67.

12 In Fig. 33-35, light travels from material a, through three layers of other materials with surfaces parallel to one another, and then back into an- other layer of material a. The refrac- tions (but not the associated reflec- tions) at the surfaces are shown. Rank the materials according to index of re- fraction, greatest first. (Hint: The par- allel arrangement of the surfaces al- lows comparison.) Figure 33-35 Question 12.

77 E Rainbow. Figure 33-67 shows a light ray entering and then leaving a falling, spherical raindrop after one internal reflec- tion (see Fig. 33-21a). The final direction of travel is deviated (turned) from the initial direction of travel by angular deviation Bdev- (a) Show that 6sey is Odey = 180° + 20, – 48, where e, is the angle of incidence of the ray on the drop and 0, is the angle of refraction of the ray within the drop. (b) Using Snell's law, substitute for 6, in terms of 6, and the index of refraction n of the water. Then, on a graphing calculator or with a computer graphing package, graph Osey versus 0, for the range of possible 6; values and for n = 1.331 for red light (at one end of the visible spectrum) and n = 1.333 for blue light (at the other end). The red-light curve and the blue-light curve have different minima, which means that there is a different angle of minimum deviation for each color. The light of any given color that leaves the drop at that color's angle of…

A ray of light crosses the boundary between some substance with n = 1.54 and air, going from the substance into air. If the angle of incidence is 29◦ what is the angle of refraction?   Calculate to 1decimal.