Question

The self inductance of the motor of an electric fan is 10 H. In order to impart maximum power at 50 Hz, it should be connected to a capacitor of capacitance ______.

Options

• 4 µF

• 8 µF

• 1 µF

• 2 µF

Answer 1

The self inductance of the motor of an electric fan is 10 H. In order to impart maximum power at 50 Hz, it should be connected to a capacitor of capacitance 1 µF.

Explanation:

L = 10 H, f = 50 Hz

For maximum power, X_C = X_L

Now, \[\frac {1}{ωC}\] = ωL

C = \[\frac {1}{ω^2L}\]

C = 1/(4π² × 50 × 50 ×10) = 0.1 × 10^-5F = 1µF