(a) Draw a diagram of light incident from air onto a thin film with n >1 with air on both sides. Indicate at which points a phase change occurs and show all reflected and refracted rays. Using this diagram, derive the condition for constructive and destructive interference for reflected light of normal incidence.
(b) A soap bubble in air has an index of refraction of 1.3. If the bubble wall is 115 nm thick, what color does the soap bubble appear to be? (Assume that white light illuminates the bubble)
