Final answer:
The property of a capacitor that opposes the flow of AC current is called capacitive reactance. It varies inversely with the frequency of the AC signal and the capacitance of the capacitor, with the formula Xc = 1 / (2πfC).
Step-by-step explanation:
The property associated with a capacitor that opposes the flow of AC current is called capacitive reactance. This is similar to resistance in a DC circuit, but specifically related to AC circuits. Capacitive reactance is a measure of how much a capacitor impedes the AC current, and it is affected by the frequency of the AC signal and the capacitance of the capacitor itself. Unlike resistors where current and voltage are in phase, for capacitors, the voltage lags behind the current by a quarter of a cycle. The formula for calculating the capacitive reactance (Xc) is given by Xc = 1 / (2πfC), where 'f' is the frequency and 'C' is the capacitance. The reactance decreases with an increase in frequency and increases with lower frequencies. At very high frequencies, the reactance is negligible, making the capacitor offer almost no opposition to the current. Conversely, at a frequency of zero (direct current), capacitive reactance becomes infinite, and a charged capacitor effectively blocks the current.