In AC circuits, the total opposition to current flow is called ____________.

In AC circuits, the total opposition to current flow is called impedance. Impedance is a comprehensive measure that combines both resistance and reactance. While resistance accounts for the opposition to direct current flow due to resistive elements, reactance arises from capacitors and inductors, which react differently to changes in current due to their respective energy storage capabilities.

Impedance is expressed as a complex quantity, often represented in polar or rectangular forms, and includes both the resistive component (real part) and the reactive component (imaginary part). This is crucial in AC circuits, where the frequency of the oscillating current can cause current and voltage to be out of phase, and understanding impedance allows for calculations relating to phase shifts, circuit behavior, and overall system performance.

Resistance, capacitance, and inductance represent components that contribute to impedance but do not encompass the overall effect of all interactions in an AC circuit. Thus, impedance is the correct term to describe the total opposition to current flow, taking into account all factors present in an AC system.