The UC Davis physicist measures the thickness of a layer of a benzene with nb = 1.50 by shining monochromatic light onto the film and varying the wavelength of the light (the film is in the air with n = 1). She finds that the light of wavelength 635 nm is reflected most strongly from the film. a) What is the minimum thickness of the film? b) What would be the wavelength of the most reflected visible light if the same layer was placed on the surface of water with nw = 1.3 while the laser still shines from the air.