A capacitor opposes any change in __________.

The correct answer is that a capacitor opposes any change in voltage.

Capacitors are devices used in electrical circuits to store and release energy. They do this by accumulating charge on their plates when a voltage is applied across them. When there is a sudden change in voltage—either an increase or a decrease—the capacitor reacts by either absorbing or supplying charge to maintain the voltage level across their terminals. This property is due to the capacitor's ability to store energy in the electric field created between its plates.

As a result, capacitors resist changes in voltage, which is why they are often used in circuits to smooth out voltage fluctuations and ensure stable operation. This characteristic is significant in applications like filtering, timing, and energy storage.

Other options like current, resistance, and power do not accurately describe the fundamental behavior of a capacitor. While capacitors do affect current in a circuit, they inherently oppose changes in voltage by design. Resistance is a property that describes how materials oppose the flow of charge, but it is not directly related to the action of a capacitor. Power is a measure of energy transfer over time, but capacitors themselves do not oppose changes in power directly; rather, their impact on the circuit influences power dynamics based on voltage and