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 increases by a factor of $\sqrt { 2 }$
B) It increases by a factor of $2 .$
C) It decreases by a factor of 4 .
D) It decreases by a factor of 2 .
E) It increases by a factor of 4 .

Question

Quizplus · Accepted Answer

The reactance of a capacitor in an AC circuit is given by $X_C = \frac{1}{2\pi fC}$, where $f$ is the frequency of the source and $C$ is the capacitance. Doubling the frequency ($f$) will halve the reactance ($X_C$), hence it decreases by a factor of 2.

A Simple Ac Circuit Is Composed of a Capacitor Connected 2\sqrt { 2 }2​

A Simple Ac Circuit Is Composed of a Capacitor Connected $\sqrt { 2 }$