As an admirer of thomas young, you perform a double-slit experiment in his honor. you set your slits 1.21 mm apart and position your screen 3.73 m from the slits. although young had to struggle to achieve a monochromatic light beam of sufficient intensity, you simply turn ona laser with a wavelength of 643 nm. how far on the screen are the first bright fringe and the second dark fringe from the central bright fringe? express your answers in millimeters.