An airplane can be made invisible to radar by coating the plane with a thin layer of an antireflective material. If radar waves have a wavelength of 3.0 cm, and the polymer has an index of refraction of n = 1.42, how thick would you make the coating? Two glass microscope slides touch on one side. On the other side, a piece of hair is inserted at the far end between the slides, with the long axis of the hair parallel to the edges of the slides. This creates an air wedge between the slides, with one end having a thickness of 0 and the other end having a thickness of the hair, which is 50 microns. How many dark fringes are observed when 600 nm light illuminates the slides from directly above.