Capacitors in AC Circuits Video Lessons

Concept

# Problem: A pure capacitor is connected to an ac power supply. In this circuit, the current A) lags the voltage by 90 degree. B) leads the voltage by 90 degree. C) lags the voltage by 180 degree. D) is in phase with the voltage. E) None of the given answers are correct.

###### FREE Expert Solution

The voltage across a capacitor in AC circuit:

$\overline{){{\mathbf{V}}}_{{\mathbf{C}}}{\mathbf{\left(}}{\mathbf{t}}{\mathbf{\right)}}{\mathbf{=}}{{\mathbf{V}}}_{{\mathbf{0}}}{\mathbf{s}}{\mathbf{i}}{\mathbf{n}}{\mathbf{\omega }}{\mathbf{t}}}$

The current across a capacitor in AC circuit:

$\overline{){{\mathbf{I}}}_{{\mathbf{C}}}{\mathbf{\left(}}{\mathbf{t}}{\mathbf{\right)}}{\mathbf{=}}{{\mathbf{I}}}_{{\mathbf{0}}}{\mathbf{s}}{\mathbf{i}}{\mathbf{n}}{\mathbf{\left(}}{\mathbf{\omega }}{\mathbf{t}}{\mathbf{+}}{\mathbf{90}}{\mathbf{°}}{\mathbf{\right)}}}$

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###### Problem Details

A pure capacitor is connected to an ac power supply. In this circuit, the current

A) lags the voltage by 90 degree.

B) leads the voltage by 90 degree.

C) lags the voltage by 180 degree.

D) is in phase with the voltage.

E) None of the given answers are correct.