A pair of narrow slits, separated by 1.8 mm, is illuminated by a monochromatic light source. Light waves arrive at the two slits in phase. A fringe pattern is observed on a screen 4.8 meters from the slits. There are 5.0 bright fringes/cm (measured from fringe center to fringe center) on the screen. What is the wavelength of the monochromatic light?