A charge of $1\mathrm{.}00C$ is fixed at the origin. A charge of $-9\mathrm{.}00C$ is fixed at $(3\mathrm{.}00cm,0\mathrm{.}00cm)$ on the $x-$axis.

a$.$ Find the location$($s$)$ of points on the $x-$axis where the electric field is zero.

b$.$ Find the location$($s$)$ of points on the $x-$axis where the electric potential is zero $($for this part, assume $V=0$

at infinity$).$

c$.$ Find the net electric field at the point $(0\mathrm{.}00cm,4\mathrm{.}00cm).$

d$.$ Find the force on an electron placed at the point $(0\mathrm{.}00cm,4\mathrm{.}00cm).$