Question

A \(70 \, \text{mH}\) inductor is connected to a \(220 \, \text{V}, 50 \, \text{Hz}\) AC supply. The RMS value of the current in the circuit is:

• A. \( \frac{100}{\sqrt{2} \pi} \, \text{A} \)
• B. \( 10 \, \text{A} \)
• C. \( \frac{50}{\pi} \, \text{A} \)
• D. \( \frac{10\sqrt{2}}{\pi} \, \text{A} \)

Hint:

For an inductive AC circuit, use \( X_L = 2\pi f L \) and \( I = \frac{V}{X_L} \).

Answer 1

The Correct Option is B

Reactance of inductor: \[ X_L = 2\pi f L = 2\pi \cdot 50 \cdot 70 \times 10^{-3} = 2\pi \cdot 3.5 = 7\pi \, \Omega \] RMS current: \[ I = \frac{V}{X_L} = \frac{220}{7\pi} \approx 10 \, \text{A} \]