Suppose the flat circular disk has a nonuniform
surface charge density $\sigma = aR^2$, where R is
measured from the center of the disk. Find the
potential at points along the x axis. (V = 0 at x =
$\infty$). Calculate it (in Volts) for the following
parameters:
$R_0 = 5.0$ cm, x = 3.0 cm, a = 3.0 $\mu C/m^4$.