Problem of the Day IV. Principle Rays In order to predict the location of an image we can draw rays from the object using the path the light takes. The figure at right is available as an enlarged pdf here: pdf link The figure shows a scale diagram with a long filament light bulb as our object and a lens with a . . , _. ;. __ __ ' ____ . _ ... ' focallengthof500m. . .. . Nd. Each square in the grid represents 10 cm X 10 cm. Complete the following on the enlargement. You can either print the PDF and draw directly on it using a ruler or other straight edge. Or, you can draw directly on the PDF electronically. You will turn in this drawing as your problem of the day. First, place an X on both sides of the lens indicating the position of the focal point. We will consider light from the top of the long filament light bulb (the point is shown on the diagram.) We know that light will travel in all directions from each point on the long filament but for our model we will first consider three of those rays called the principle rays. Carefully draw the principle rays using the following rules: Ray 1 is drawn from the object (the top part of the filament) to the lens along a line parallel to the principle axis. At the middle of the lens this ray bends and travels in a straight path through the focal point. Ray 2 is drawn from the object along a line through the exact center of the lens and does not bend. Ray 3 is drawn from the object through the focal point to the lens. This ray bends at the middle of the lens and continues along a straight path along a line parallel to the principle axis. Light bends when it strikes the lens (not in mid-air)! For simplicity in our drawings we can bend all of the rays at the middle of the lens. The lens simulation from the previous part of the lab gives an example of these three rays. Ray 1 (red) Focal Points When you have completed drawing the rays snap a phone photo or take a screen shot and upload your image below