In a rectangular waveguide for which a $=1\mathrm{.}5$ cm$,$ b $=0\mathrm{.}8$ cm$,=0,=0$ and $=40,$ Hx $=2$ sin $($x$/$a$)$ cos $(3$y$/$b$)$ sin $(\backslash$times $1011$t $-$ z$)$ A$/$mDetermine for TE$13$ mode$($a$)$ The mode of operation$($b$)$ The cutoff frequency$($c$)$ The phase constant $($d$)$ The propagation constant $($e$)$ The intrinsic wave impedance $.$