Q $2($b$)$

$[6$ Marks$]$

In the case of a Young's double slits experiment using a dual wavelength source, with spectral lines at $455$ nm and $250$ nm $,$ and a slit separation of $\backslash (10\backslash$mu $\backslash$mathrm$\{$~m$\}\backslash ),$ at what angular position $($apart from $\backslash (\backslash$theta$=0^\{\backslash$circ$\}\backslash ))$ will the intensity maxima of both lines coincide perfectly for the first time? You must first determine the interference orders for this condition for both lines.