A copper wire $($diameter $1\mathrm{.}02$ mm$)$ carries a current with a current density of $3\mathrm{.}20106$ A$/$m$2.$ The density of free electrons for copper is $8\mathrm{.}51028$ electrons per cubic meter. Calculate $($a$)$ the current in the wire and $($b$)$ the drift velocity of electrons in the wire