A $2\mathrm{.}0-$mm$-$diameter wire formed from a composite material has a resistivity that decreases with distance along the wire as $=$$0$e$$x$,$ where $0=2\mathrm{.}5105$m$,$ x $($in m$)$ is measured from one end of the wire, and the constant $=4\mathrm{.}0$ m$1.$