A capacitor passes a current of 12.6 mA when supplied with 20 V ac with a frequency of 1 kHz. The capacitance of the capacitor is
- A. 0.1 $\mu$F
- B. 0.1 pF
- C. 1 $\mu$F
- D. 1 F
Answer: A. 0.1 $\mu$F
Explanation: $X_c = \frac{1}{\omega c}$ and $V = I X_c = \frac{I}{\omega c}$. $c = \frac{I}{2\pi f V} = \frac{12.6\times 10^{-3}}{2\pi \times 1\times 10^3 \times 20} = 0.1~\mu$F.