[填空题]
Monochromatic light fallse yw0 p7z:)umv ovp;ul9nwxe wlz w: .x2 /:m+sin a slit that is $ 2.60\times10^{ -3}\;mm$ wide. If the angle between the first dark fringes on either side of the central maximum is 35.0$^{\circ}\,$ (dark fringe to dark fringe), what is the wavelength of the light used? nm
