Problem $6$:

A single slit of width a$=2\mathrm{.}125\backslash$mu m is illuminated by a collimated beam of $\backslash$lambda $=550$nm$.$

$($a$)$ Determine the angular radius of the central peak.

$($b$)$ Find the intensity ratio $($I$)/($I$\_(0))$ at $\backslash$theta $=5\backslash$deg $,10\backslash$deg $,15\backslash$deg $,$ and $22\mathrm{.}5\backslash$deg $.$