*66 o In Fig. 33-62, a light ray in air is incident at angle 6, on a block of transparent plastic with an index of refraction of 1.56. The dimen- sions indicated are H= 2.00 cm and W = 3.00 cm. The light passes through the block to one of its sides and there undergoes reflection (in- side the block) and possibly refraction (out into the air). This is the point of first reflection. The re- flected light then passes through the block to another of its sides-a point of second reflection. If 6 = 40°, on which side is the point of (a) first reflection and (b) second reflection? If there is refraction at the point of (c) first reflection and (d) second reflection, give the angle of refraction; if not, answer "none." If 61 = 70°, on which side is the point of (e) first reflection and (f) second reflection? If there is refrac- tion at the point of (g) first reflection and (h) second reflection, give the angle of refraction; if not, answer “none." н Figure 33-62 Problem 66.

..54 Dispersion in a window pane. In gle e Fig. 33-54, a beam of white light is incident at an- 50° on a common window pane (shown in cross section). For the pane's type of glass, the index of refraction for visible light ranges from 1.524 at the blue end of the spectrum to 1.509 at the red end. The two sides of the pane are paral- lel. What is the angular spread of the colors in the beam (a) when the light enters the pane and (b) when it emerges from the opposite side? (Hint: When you look at an object through a window pane, are the colors the light from the object dispersed as shown in, say, Fig. 33-20?) = Ꮎ Figure 33-54 Problem 54.

White light is sent through an interface of a 100% (w/v) glycerol solution (n = 1.474) and a 20% (w/v) sucrose solution (n2 = 1.364) at an angle of Oj. Incident ray Reflocted ray If O, = 33', determine the angle of O2 in degrees. Refructive index = , O2 Refractive index – n, If O, = 0, determine the angle of 02 in degrees. Refractod ray

10. A light ray of given wavelength, initially in air, strikes a 90° prism at P (see Fig. 39-53) and is refracted there and at Q to such an extent that it just grazes the right-hand prism surface at Q. (a) Determine the index of retraction of the prism for this wavelength in terms of the angle of incidence , that gives rise to this situation. (b) Give a numerical upper bound for the index of refraction of the prism. Show, by ray dia- grams, what happens if the angle of incidence at P is (c) slightly greater or (d) slightly less than 0₁. 90 FIGURE 39-53. Problem 10.

A ray of light is incident on an air/water interface. The ray makes an angle of θ1 = 29 degrees with respect to the normal of the surface. The index of the air is n1 = 1 while water is n2 = 1.33. Write an expression for the reflection angle ψ, with respect to the surface.

If the apex angle of a prism is $ = 75° (see Fig. 23–63), what is the minimum incident angle for a ray if it is to emerge from the opposite side (i.e., not be totally internally reflected), given n = 1.58? FIGURE 23-63 Problem 77.