Wave Optics: Interference through thin films.
1.) A mixture of yellow light (wavelength = 582 nm in vacuum) and violet light (wavelength = 414 nm in vacuum) falls perpendicularly on a film of gasoline that is floating on a puddle of water. For both wavelengths, the refractive index of gasoline is n = 1.40 and that of water is n = 1.33. What is the minimum nonzero thickness