A capacitor is connected across an oscillating emf with a peak current through the capacitor of 7.00 A. If the frequency ω is doubled, what is the peak current?
7.00 A
4.95 A
3.50 A
14.0 A
1 Answer
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The reactance (a bit like resistance) of a capacitor is Z = 1/(ωC) = 1/(2πfC)
Look at the formula – doubling ω halves the reactance. It’s a bit like halving the resistance in a simple DC circuit. So current doubles from 7A to 14A.
