laser light of wavelength 632.8 nm falls normally on a slit that is 0.0250 mm wide. the transmitted light is viewed on a distant screen where the intensity at the center of the central bright fringe is 8.50 w/m2. a) find the total number of dark fringes on the screen. b) at what angle does the dark fringe that is most distant from the center occur? c) what is the maximum intensity of the bright fringe that occurs immediately before the dark fringe in part b)?