Dielectric Polarization and Polarization Charges

A dielectric placed in the plate capacitor. Due to the electric field \(E\), dipoles are induced in the dielectric, i.e. electrons of the dielectric are shifted to the positive pole of the capacitor (however, the electrons can only be shifted within the atoms). While inside the dielectric the positive and negative charges lift away, a negatively charged surface forms at one edge of the dielectric and a positively charged surface at the other edge. This creates an opposing electric field \(E_{\text p}\) in the dielectric, which opposes the E-field of the capacitor. The resulting electric field in the dielectric is therefore smaller than \(E\).

Consequently, a dielectric reduces the external electric field.