Please help me with this i need a 10 sentence answer if you don’t know how to answer with 10 sentences ignore it or I will report you

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 480 ? the index of refraction of the film is 1.34, and there is air on both sides of the film. express your answer in nanometers. hint 1. how to approach th