Deep Dive: G5A09
The correct answer is B: Ohm. The unit used to measure reactance is the ohm. Reactance, like resistance, is measured in ohms (Ω). For amateur radio operators, this is a fundamental unit. Understanding this helps when working with reactance values.
Why Other Answers Are Wrong
Option A (Farad): Incorrect. Farad is the unit for capacitance, not reactance. Capacitance is measured in farads, reactance in ohms. Option C (Ampere): Incorrect. Ampere is the unit for current, not reactance. Current is measured in amperes, reactance in ohms. Option D (Siemens): Incorrect. Siemens is the unit for conductance/admittance, not reactance. Admittance is measured in siemens, reactance in ohms.
Exam Tip
Reactance unit = ohm. Think 'R'eactance = 'R'esistance-like, so 'O'hm. Reactance, like resistance, is measured in ohms (Ω). Not farad (capacitance), not ampere (current), not siemens (admittance) - just ohm.
Memory Aid
Reactance unit = ohm. Think 'R'eactance = 'R'esistance-like, so 'O'hm. Reactance, like resistance, is measured in ohms (Ω). Standard unit for reactance measurement.
Real-World Example
An inductor has 100 ohms of inductive reactance at a certain frequency. A capacitor has 50 ohms of capacitive reactance. Reactance is measured in ohms, just like resistance. The ohm is the unit for both resistance and reactance.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G5A
Reference: 2023-2027 Question Pool · G5 - Electrical Principles
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G5A topic.