$2.($a$)$ Consider the circuit in Figure $2\mathrm{.}1$ where the switch $\backslash ($ S $\backslash )$ has been closed for a very long time. The switch is open at $\backslash ($ t$=0\backslash ).$ Using time domain analysis, determine the voltage $\backslash ($ v$($t$)\backslash )$ for $\backslash ($ t$>0\backslash ).$

Figure $2\mathrm{.}1$

$(13$ Marks$)$