What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 520 ? The index of refraction of the film is 1.34, and there is air on both sides of the film.
Im wondering do I use the equation for constructive 2nt=m*lamda OR destructive 2nt=(m+1/2)*lambda??<--- this is mainly where I am confused.
The Attempt at a Solution