What property of a capacitor allows it to store electrical energy?

The ability of a capacitor to store electrical energy is fundamentally linked to the dielectric material that separates its conductive plates. This dielectric, an insulator, not only prevents direct current (DC) from passing between the plates but also allows the electric field created by the charges on the conductive plates to build up.

When a voltage is applied across the capacitor, the plates accumulate equal amounts of positive and negative charge, resulting in an electric field being generated in the dielectric material. The energy is stored in this electric field, allowing the capacitor to discharge it later when needed within an electrical circuit.

While conductive plates are essential for accumulating charge, they alone do not enable energy storage without the presence of a dielectric. Ohmic resistance is related to the dissipation of energy rather than storage, and magnetic fields pertain to inductors, not capacitors. Thus, the dielectric material is crucial for the energy storage capability of a capacitor.