1. The problem statement, all variables and given/known data Monochromatic light, at normal incidence, strikes a thin film in air. If (lambda) denotes the wavelength in the film, what is the thinnest film in which he reflected light will be a maximum? 2. Relevant equations 2d = (m+1/2)(lambda/nfilm) for minimal reflection and 2d = m(lambda/nfilm) for max reflection 3. The attempt at a solution I used the second formula above: 2d = m(lambda/n) and solved for d; I got d = lambda/2n , but someone else in my class says it is lamba/4n, Can anyone offer any insight? Thanks!!