Nate Electrical Practice Exam

How is impedance best defined?

1. Opposition to alternating current flow

2. Electrical flow

3. Amperage

4. Electrical pressure

The correct answer is: Opposition to alternating current flow

Impedance is best defined as the opposition to alternating current (AC) flow. This term encompasses not only resistance, which is the opposition to direct current (DC), but also includes reactance, which arises from capacitors and inductors in an AC circuit. Reactance varies with frequency, meaning that impedance is a frequency-dependent quantity that affects how AC circuits behave. When working with AC circuits, impedance is crucial because it fully characterizes how electrical energy flows within the circuit. It is measured in ohms, the same unit as resistance, but it captures a more comprehensive view of how different circuit components interact under alternating current conditions. In contrast, the other options refer to different concepts that do not encapsulate the complete definition of impedance. Electrical flow refers to the current itself rather than the opposition to it. Amperage is a measure of the current in the circuit and does not describe how opposition is presented in AC circuits. Electrical pressure, which could refer to voltage or electromotive force, indicates the driving force behind current flow but does not pertain to the opposition that impedance represents.