In a young's double-slit experiment, a set of parallel slits with a separation of 0.142 mm is illuminated by light having a wavelength of 576 nm and the interference pattern observed on a screen 3.50 m from the slits. (a) what is the difference in path lengths from the two slits to the location of a fourth order bright fringe on the screen? μm (b) what is the difference in path lengths from the two slits to the location of the fourth dark fringe on the screen, away from the center of the pattern? μm