14.1 Answer the following questions using complete sentences. Questions asking for math solutions require a legible picture of your work included in the document, ask your instructor for help with this if you need it. Be sure to include units on questions involving math. 1. On a bright, sunny day you can use a magnifying glass to burn wood by focusing sunlight onto it. The focused sunlight forms a small circular spot of light that heats the wood until it burns. Why is the spot of light circular? 2. One part of a fiber optic communication system uses a lens to focus light from a semiconductor laser onto the end of an optical fiber. The tiny light source and fiber are on opposite sides of the lens, and each is 1.0 cm away from the lens. Why must the lens have a focal length of 0.5 cm? 3. Your new 35-mm camera comes with two lenses: a 50-mm focal length "normal" lens and a 200-mm focal length "telephoto" lens. The minimum f-number for the 50-mm lens is 1.8. Although the 200-mm lens has much larger glass elements in it, its lowest f-number is 4. Why is the telephoto lens's