4.5

A thin film of gasoline is floating on water. Sunlight, which contains all wavelength of visible light, shine directly on to the gasoline/water mixture. We would like to calculate the thicknesses of gasoline that will allow use to see 600 nm light reflected. The index of refraction for gasoline is 1.2 and the index of refraction for water is 1.33. (a) What equation would use to calculate these thickness? Explain all the details for why you have chosen this equation. (b) Calculate the smallest thickness that will reflect this wavelength of light. (c) Are there any other visible wavelengths that be reflected at this thickness? If yes, which are they? If not, how do you know