An oil film (n = 1.45) floating on water is illuminated by white light at normal incidence.

Question:

An oil film (n = 1.45) floating on water is illuminated by white light at normal incidence. The film is 280 nm thick. Find
(a) The color of the light in the visible spectrum most strongly reflected and
(b) The color of the light in the spectrum most strongly transmitted. Explain your reasoning.