An oil tanker spills a large amount of oil (n = 1.45) intothe sea (n = 1.33). 

(a) If you look down onto the oil spill from overhead, what predominant wavelength of light do you see at a point where the oil is 380 DIn thick? What color is the light? 

(b) In the water under the slick, what visible wavelength (as measured in air) is predominant in the transmitted light at the same place in the slick as in part (a)?