The energy stored by a capacitor is called __________.

• A. Capacitance
• B. Magnetic energy
• C. Electrostatic charge
• D. Electric potential energy

Answer: (C)

The energy stored in a capacitor is electric potential energy. When a capacitor is charged, it creates an electric field between its plates, and the work done to assemble that charge is stored as energy in that field. For a capacitor with capacitance C charged to voltage V, the stored energy is U = (1/2) C V^2, which can also be written as U = (1/2) Q V since Q = C V. This shows energy depends on both how much charge sits on the plates and the voltage across them, not on the amount of charge alone. Capacitance is a property that describes how much charge per volt the device can store, while electrostatic charge is the amount of charge itself. Magnetic energy, on the other hand, is stored in magnetic fields and relates to inductors, not capacitors.