a. A ray of light enters a fiber optic cable with index of refraction n from air at an angle e as shown below. Let the angle 0 be 69°. For total internal reflection to occur at the cable-air interface, what must be the value of n? Dair - 1 n = Ꮎ θα ec n

Consider a light ray that enters a pane of glass with air on one side and water on the other side as shown in Figure P38.21. The light ray experiences refraction at the first interface when it enters the glass from the water and again at the second interface when it exits the glass into the air. Assume the index of refraction of the glass is 1.54. For a ray of light, find the angle of incidence 1 in the water such that the ray experiences total internal reflection when it strikes the glassair interface on the other side. FIGURE P38.21

Curved glassair interfaces like those observed in an empty shot glass make it possible for total internal reflection to occur at the shot glasss internal surface. Consider a glass cylinder (n = 1.54) with an outer radius of 2.50 cm and an inner radius of 2.00 cm as shown in Figure P38.105. Find the minimum angle i such that there is total internal reflection at the inner surface of the shot glass. FIGURE P38.105 Problems 105 and 106.

N A fish is 3.25 m below the surface of still water. Because of total internal reflection, it is hidden from the view of a fisher in a boat on the water as long as the boat is outside a circle of radius r. The center of the circle is directly above the fish (Fig. P38.16). Find the minimum value of r.

A ray of light strikes a flat, 2.00-cm-thick block of glass (n = 1.50) at ail angle of 30.0 with respect to the normal (Fig. P22.18). (a) Find the angle of refraction at the lop surface. (b) Find the angle of incidence at the bottom surface and the refracted angle. (c) Find the lateral distance d by which the light beam is shifted. (d) Calculate the speed of light in the glass and (e) the time required for the light to pass through the glass block. (f) Is the travel time through the block affected by the angle of incidence? Explain.

Unreasonable results Light traveling from water to a gemstone strikes the surface at an angle of 80.00 and has an angle of refraction of 15.2°. (a) What is the speed of light in the gemstone? (b) What is unreasonable about this result? (c) Which assumptions are unreasonable or inconsistent?

A person looking into an empty container is able to see the far edge of the containers bottom, as shown in Figure P22.23a. The height of the container is h, and its width is d. When the container is completely filled with a fluid of index of refraction n and viewed from the same angle, the person can see the center of a coin at the middle of the containers bottom, as shown in Figure P22.23b. (a) Show that the ratio h/d is given by hd=n214n2 (b) Assuming the container has a width of 8.00 cm and is filled with water, use the expression above to find the height of the container.

The Sun appears at an angle of 53.0 above the horizontal as viewed by a dolphin swimming underwater. What angle does the sunlight striking the water actually make with the horizon?