Answer
The magnitude of the electric force on the electron is $~~2.1\times 10^{-17}~N$
Work Step by Step
We can find the strength of the electric field between $x = 1.0~cm$ and $x = 4.0~cm$:
$E = -\frac{\Delta V}{\Delta x}$
$E = -\frac{6.0~V-2.0~V}{0.040~m-0.010~m}$
$E = -133~V/m$
Since the electric field points from higher potential to lower potential, the electric field is in the -x direction.
Note that the charge on an electron is negative.
We can find the force on the electron:
$F = q~E$
$F = (-1.6\times 10^{-19}~C)(-133~V/m)$
$F = 2.1\times 10^{-17}~N$
The magnitude of the electric force on the electron is $~~2.1\times 10^{-17}~N$.
