In a Young's double-slit experiment, two rays of monochromatic light emerge from the slits and meet at a point on a distant screen, as in the drawing. The point on the screen where these two rays meet is the 7th-order bright fringe. The difference in the distances that the two rays travel is 4.48 x 10-6 m. What is the wavelength (in nm) of the monochromatic light?