Question

A simple ac circuit is composed of a capacitor connected across the terminals of an ac power source. If the frequency of the source is doubled, what happens to the reactance of the capacitor?

A.It decreases by a factor of 2
B.It decreases by a factor of 4
C.It increases by a factor of 4.
D. It increases by a factor of sqrt(2)
E.It increases by a factor of 2.

Answer 1

When the frequency of the AC power source in a circuit with a capacitor is doubled, the capacitive reactance decreases by a factor of 2. The correct option is A.

Step-by-step explanation:

If the frequency of the AC power source in a simple AC circuit with a capacitor is doubled, the capacitive reactance (Xc) is inversely related to the frequency, which means that Xc decreases. The capacitive reactance of a capacitor is given by the equation Xc = 1 / (2πfC), where f is the frequency and C is the capacitance.

Since the capacitive reactance is inversely proportional to the frequency, doubling the frequency will halve the reactance, so the correct answer is:

A. It decreases by a factor of 2.