Question

If an inductor of inductance \(0.5 \, \mu H\) is connected to an AC source of frequency 70 MHz and voltage 3.3 V, then the current through the inductor is:

• A. 5 mA
• B. 7.5 mA
• C. 15 mA
• D. 30 mA

Hint:

For inductors in AC circuits, current \( I = \frac{V}{2\pi f L} \). Calculate inductive reactance first.

Answer 1

The Correct Option is C

Given data: \[ L = 0.5 \, \mu H = 0.5 \times 10^{-6} \, H, f = 70 \, {MHz} = 70 \times 10^6 \, {Hz}, V = 3.3 \, V \] The inductive reactance \( X_L \) is: \[ X_L = 2 \pi f L = 2 \pi \times 70 \times 10^6 \times 0.5 \times 10^{-6} = 2 \pi \times 35 = 219.91 \, \Omega \] The current \( I \) through the inductor is: \[ I = \frac{V}{X_L} = \frac{3.3}{219.91} \approx 0.015 \, A = 15 \, mA \]