1. The problem statement, all variables and given/known data A uniform film of oil (n=1.31) is floating on water. When sunlight in air is incident normally on the film, an observer finds that the reflected light has a maximum at wavelength (lambda) = 450nm and a minimum at wavelength (lambda) = 600nm. What is the thickness of the oil film? 2. Relevant equations The light equations for constructive and destructive interference. 2t = (m + 1/2) lambda / n and 2t = m * (lambda / n) 3. The attempt at a solution I am having difficulties knowing where to start. We haven't had a question like this before.