You are spin coating a thin layer of polymer onto a reflective silicon wafer to create an organic solar cell device. The polymer film layer, upon solvent evaporation, is roughly 300 nm thick (although you are not exactly sure of the thickness). The refractive index of the polymer is 2.6. When you look straight down at the film you notice that green light (500 nm wavelength) is clearly visible. What thickness would you determine the film to be?