A technician is designing a capacitor using an insulating material as the dielectric. When an external electric field is applied to the capacitor, the technician observes that the dielectric material becomes polarized. How does this polarization affect the electric field within the capacitor?

When the external electric field hits the dielectric, the molecules inside shift so their positive and negative sides line up opposite to the field, creating a small internal field that points against the applied one. This internal field partially cancels the original field, so the net electric field inside the capacitor is weaker than it would be without the dielectric. Because the field is reduced, the capacitor can store more charge for the same applied voltage, which is why dielectrics increase capacitance. For example, if a 1‑volt potential is applied to a capacitor with a dielectric that reduces the field by half, the capacitor can hold twice as much charge as an air‑filled one. Thus, polarization lowers the internal field and boosts the capacitor’s ability to store energy.