In Young's double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths ${\lambda _1}$ = 12000 $\mathop A\limits^ \circ $ and ${\lambda _2}$ = 10000 $\mathop A\limits^ \circ $. At what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?