$13\mathrm{.}23\mathrm{.}3($a$)$ Calculate the drain current in an NMOS transistor with parameters VTN $=0\mathrm{.}4$V$,$ kn $=120$A$/$V$2,$ W $=10$m$,$ L $=0\mathrm{.}8$m$,$ and with ap plied voltages of VDS $=0\mathrm{.}1$V and $($i$)$ VGS $=0,($ii$)$ VGS $=1$V$,($iii$)$ VGS $=2$V$,$ and $($iv$)$ VGS $=3$V$.($b$)$ Repeat part $($a$)$ for VDS $=4$V$.$