A circular disk of radius R has a uniform surface charge density a. determine the electric field at a point on the axis

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A circular disk of radius R has a uniform surface charge density
a. determine the
electric field at a point on the axis of the disk at a distance z
from the plane of the disk. (b) a cylinder
right circular, of radius R and height L, is oriented along the z
axis. It has a volumetric density
non-uniform charge given by p(z) = Po + Bz with respect to an
origin at the center of the cylinder.
Determine the force on a point charge q located at the center of
the cylinder.