Question

A 21 nF capacitor is connected across an AC generator that produces a peak voltage of 4.0 V.

At what frequency f is the peak current 44 mA?

Answer 1

Vc = ( 1/(2 $\pi$ f*C) ) * Im

Vc/Im = ( 1/(2 $\pi$ f*C) )

Im/Vc = 2 $\pi$ f*C

f = (Im/Vc) (1/(2 $\pi$ C))

f = ( 44*10^-3 A / 4.0 V) ( 1 / ( 2 $\pi$ *21*10^-9 F )
f = 8.33*10⁴ Hz