Question

Calculate the rms value of current in the circuit wherein an 80 μF capacitor is connected to a 100 V, 80 Hz ac supply.

(a) 4 A

(b) 2 A

(c) 7 A

(d) 50 A

The question was posed to me in a job interview.

Asked question is from AC Voltage Applied to a Capacitor in division Alternating Current of Physics – Class 12

Answer 1

Correct option is (a) 4 A

For explanation: Xc = \(\frac {1}{2πfC}\)

Xc = \(\frac {1}{(2 \times 3.14 \times 80 \times 80 \times 10^{-6})}\)

Xc = 24.8 Ω.

Irms = \(\frac {E_{rms}}{X_C}\)

Irms = \(\frac {100}{24.8}\)

Irms = 4.03 A ≈ 4 A.