N optician is performing Young's double-slit experiment for her clients. She directs a beam of monochromatic light to a pair of parallel slits, which are separated by 0.134 mm from each other. The portion of this light that passes through the slits goes on to form an interference pattern upon a screen, which is 4.50 meters distant. The light is characterized by a wavelength of 553 nm. (a) What is the optical path-length difference (in µm) that corresponds to the fourth-order bright fringe on the screen? (This is the fourth fringe, not counting the central bright band, that one encounters moving from the center out to one side.)