QUESTION FIVE List one optical and one magnetic computer storage devices. For each, briefly explain how data is stored and retrieved from the device. (8 marks) A light ray entering an optical fiber surrounded by air is first refracted and then reflected as shown in Figure 2. Show that if the fiber is made from crown glass, any incident ray will be totally internally reflected. a. b. nn Figure 2 A light ray enters the end of a fiber, the surface of which is perpendicular to its sides. Examine the conditions under which it may be totally internally reflected. (8 marks) C. A 2.00-cm-high object is placed 3.00 cm in front of a concave mirror. If the image is 5.00 (4 marks) cm high and virtual, what is the focal length of the mirror?