Asolid cylinder (centered along the z-axis, bottom face at z =0, top face at z=l, radius r) carries a volume charge distribution p(z) = kz, where k is a positive constant. a. calculate the electric field at an arbitrary point on the z-axis (x= 0, y = 0, z). b. write an integral expression for the electric field at an arbitrary point (x, y, z). c. sketch the electric field.