What is the unit of impedance?

• A. Volt
• B. Watt
• C. Ohm
• D. Farad

Answer: (C)

Impedance is a crucial concept in electrical engineering and electronics, representing the total opposition that a circuit presents to the flow of alternating current (AC) at a given frequency. The unit of impedance is the ohm, which is denoted by the symbol Ω.

This unit is used to quantify both resistance (the opposition to current flow in a direct current, DC, circuit) and reactance (the opposition to current flow caused by capacitors and inductors in AC circuits). In essence, impedance extends the idea of resistance to AC circuits by combining both resistive and reactive components, thus providing a more comprehensive understanding of how circuits behave under varying frequencies. When analyzing AC circuits, understanding and calculating impedance is key to designing effective and efficient systems, making the ohm a fundamental unit in both ham radio and broader electronic applications.

The other choices represent different electrical units: volts measure electric potential, watts measure power, and farads measure capacitance. Each serves a unique purpose in the study of electricity and electronics, but they do not relate to the concept of impedance.