A soap film (n = 1.33) is formed in a loop of wire that is mounted vertically is not exactly uniform in thickness becauseof its weight, but wedge-shaped in cross section. When the film is illuminated with yellow light of wavelength 585 nm, onesees that a distance of 3.40 cm separates two bright fringes that are 4 orders apart. By how much does the film differ inthickness over this distance?

A soap film (n = 1.33) is formed in a loop of wire that is mounted vertically is not exactly uniform in thickness becauseof its weight, but wedge-shaped in cross section. When the film is illuminated with yellow light of wavelength 585 nm, onesees that a distance of 3.40 cm separates two bright fringes that are 4 orders apart. By how much does the film differ inthickness over this distance?