A dielectric object that has a quasi-permanent polarization when the applied field is 0 is called an electret. Consider a uniformly polarized electret in the shape of a cylinder of height h and radius 10h. The polarization in the dielectric is P k^, where k^ is parallel to the cylinder axis.

(a) Sketch the electric field lines.
(b) Calculate the electric field E at the center of the cylinder. Because the radius is large compared to the height, you may neglect edge effects