Impedance in an electric circuit is the combination of which properties?

Impedance in an electric circuit represents the total opposition that a circuit presents to the flow of alternating current (AC). It is a complex quantity that combines two fundamental properties of electrical circuits: resistance and reactance.

Resistance pertains to the opposition to current flow due to the material itself, causing energy dissipation as heat. Reactance, on the other hand, accounts for the opposition to current flow caused by the circuit's inductors and capacitors, which store energy temporarily in magnetic or electric fields, respectively.

When both of these properties are considered together, they form the overall impedance, expressed as a complex number in polar or rectangular form. This combination allows for a complete understanding of how AC circuits behave under various conditions.

The other options do not accurately reflect the definition of impedance. Voltage and current refer to the electrical quantities involved in generating power, but they do not encompass the concept of how an AC circuit resists current flow. Power and current describe the relationship between electrical energy and motion of charge, while voltage and frequency also do not represent opposition to current flow in the way that resistance and reactance do.