In a double$-$slit interference experiment, the wavelength is $2=6\mathrm{.}3$

x$10-7$ m$,$ the slit separation is d $=5\mathrm{.}3$ x$10-3$ m$.$ Only consider the

bright fringes on one side of the central bright fringe. If the linear distance between the $2$nd order bright fringe and the $6$th order bright fringe on the screen is $6\mathrm{.}8$ x$10-3$ m$,$ what is the distance L $($unit in m$)?$