Nate Electrical Practice Exam

What does impedance in a circuit result from?

1. Pure resistance

2. Inductive reactance

3. Capacitive reactance

4. All of the above

The correct answer is: All of the above

Impedance is a comprehensive measure of how a circuit resists the flow of alternating current (AC), and it encompasses not only pure resistance but also the effects of reactance, which can be either inductive or capacitive. Pure resistance contributes to impedance by opposing the flow of current in a consistent manner regardless of frequency. This is the component of impedance that remains constant in both AC and direct current (DC) circuits. Inductive reactance arises from inductors in the circuit, which oppose changes in current due to the magnetic field they create. This reactance increases with frequency, meaning that the opposition to current flow changes depending on the AC frequency. Capacitive reactance, on the other hand, occurs in circuits with capacitors, which store energy in an electric field. Like inductive reactance, capacitive reactance also varies with frequency, but it does so in a direction opposite to inductive reactance. When these elements are combined in a circuit, the resulting impedance is a vector sum of all these components. Therefore, stating that impedance results from all three factors—pure resistance, inductive reactance, and capacitive reactance—accurately captures the full picture of how circuits behave in the presence of AC signals