Which variable represents capacitance in the capacitive reactance formula?

• A. f
• B. C
• C. Xc
• D. L

Answer: (B)

The variable that represents capacitance in the capacitive reactance formula is denoted by C. Capacitance measures a capacitor's ability to store electric charge, and it is measured in farads (F). In the context of capacitive reactance, capacitance is the key factor that affects how much opposition a capacitor provides to alternating current (AC).

The capacitive reactance itself is calculated using the formula:

[ X_c = \frac{1}{2\pi f C} ]

In this formula, Xc represents the capacitive reactance, f is the frequency of the AC signal, and C is the capacitance. Higher capacitance results in lower reactance for a given frequency, meaning the capacitor will allow more AC to pass through. This understanding is fundamental in circuits involving capacitors.

The other choices relate to different electrical concepts. For example, frequency (f) pertains to how often the AC cycle occurs, Xc represents the reactance itself, and L represents inductance, which is associated with inductors rather than capacitors. Thus, C is the only choice that directly represents capacitance in the context of capacitive reactance.