A sheet of glass having an index of refraction of 1.45 is to be coated with a film of material having an index of refraction of 1.68 in order that green light with a wavelength of 547 nm (in air) will be preferentially transmitted via constructive interference. (a) What is the minimum thickness of the film that will achieve the result? (b) Are other parts of the visible spectrum also preferentially transmitted? (c) Will the transmission of any colors be sharply reduced?