Isaac Newton, working in a dark room, let a beam of sunlight pass through a hole in the window shade. His goal was to show that white light is composed of all the colors. He placed a prism in the path of the beam and saw that the white light spread out to form a color spectrum. To prove that the colors were not produced by the prism, he used a screen with a small slit to select one color of light. He then placed a second prism in the path of this monochromatic (one-color) beam.
a. What colors emerged from the second prism?
b. Next, Newton removed the filter (the slit) and used the second prism to form a beam of white light (Fig. P38.27). Why was this step necessary?
