Final answer:
The correct statement is A: The discharge of a capacitor changes the direction of the current. During the charge-discharge cycle, the voltage and current of a capacitor change periodically, with the capacitance being dependent on its geometry and materials, not voltage.
Step-by-step explanation:
The statement that best describes the movement of electrical current when a capacitor is used in a circuit is A: The discharge of a capacitor changes the direction of the current. When a capacitor is charging, the current flows into the capacitor, increasing the voltage across it. As the capacitor discharges, the electric charge flows out of the capacitor, and the voltage across it decreases, which can lead to a change in the direction of the current if the capacitor is part of an AC circuit. During a full charge-discharge cycle, the voltage across a capacitor will start at a maximum when fully charged, leading to zero current flow because the capacitor obstructs further current flow. As the capacitor discharges, the voltage decreases, and current flow can change direction. Over time, as the capacitor recharges, the voltage rises again, resulting in a periodic change in current direction. Capacitors store electrical energy in the electric field between their plates, and the capacitance depends on the geometry of the capacitor and the dielectric material between the plates, but not on the voltage across the capacitor.