Which unit is used to measure impedance according to the material?

Which unit is used to measure impedance according to the material?

• A. Ohms
• B. Henries
• C. Farads
• D. Watts

Answer: (B)

Impedance is the opposition an AC circuit offers to current flow, combining resistance and reactance. Its unit is the ohm, the same unit used for resistance, because impedance is defined as Z = V/I, so the units are volts per ampere, which reduces to ohms. Even though reactance varies with frequency and components, the overall quantity that describes opposition to current carries the same unit as resistance. Inductance is measured in henries, capacitance in farads, and power in watts, but those units describe separate properties, not impedance. So the unit used to measure impedance is ohms.

Impedance is the opposition an AC circuit offers to current flow, combining resistance and reactance. Its unit is the ohm, the same unit used for resistance, because impedance is defined as Z = V/I, so the units are volts per ampere, which reduces to ohms. Even though reactance varies with frequency and components, the overall quantity that describes opposition to current carries the same unit as resistance. Inductance is measured in henries, capacitance in farads, and power in watts, but those units describe separate properties, not impedance. So the unit used to measure impedance is ohms.