Question 41

The Correct Answer is C ### Why Option C ("ohms") is correct: Capacitive reactance ($X_C$) is the opposition offered by a capacitor to the flow of alternating current (AC). Since reactance is a form of opposition to current flow, it is functionally equivalent to resistance or impedance in terms of its effect on the circuit's current. Because resistance and impedance are measured in ohms ($\Omega$), capacitive reactance must also be expressed in the unit of **ohms**. Mathematically, capacitive reactance is defined by the formula $X_C = \frac{1}{2\pi fC}$, where $f$ is frequency (Hz) and $C$ is capacitance (Farads). When the units of the terms on the right side of the equation are analyzed, the resulting unit is ohms. ### Why the other options are incorrect: * **A) henrys:** The henry (H) is the standard unit of **inductance** ($L$), which is the property of a circuit component (like an inductor) to oppose changes in current. * **B) mhos:** The mho (ohm spelled backward, sometimes called the Siemens, S) is the unit of **conductance** or **admittance**. Conductance is the reciprocal of resistance, and admittance is the reciprocal of impedance (or reactance). While related to reactance, the mho is the unit of the reciprocal property, not the reactance itself. * **D) farads:** The farad (F) is the standard unit of **capacitance** ($C$), which is a measure of a capacitor's ability to store an electrical charge. Capacitance is the physical property of the component, whereas capacitive reactance is the opposition offered by that component at a specific frequency.