Question

In a purely inductive circuit, the power factor is

• A. 0
• B. 1
• C. 0.5
• D. infinity

Hint:

In purely inductive circuits, the current lags the voltage by 90°, leading to a power factor of zero.

Answer 1

The Correct Option is A

Step 1: Power factor in an AC circuit.
The power factor (\( \text{PF} \)) in an alternating current (AC) circuit is the cosine of the phase angle (\(\theta\)) between the current and voltage. For purely inductive circuits, the phase angle between current and voltage is \(90^\circ\).
Step 2: Power factor for purely inductive circuits.
The power factor in a purely inductive circuit is given by: \[ \text{PF} = \cos(90^\circ) = 0 \]
Step 3: Analyze options.
- (A) 0: Correct. In a purely inductive circuit, the power factor is zero because current lags the voltage by 90° and no real power is transferred.
- (B) 1: Incorrect. A power factor of 1 happens only in a purely resistive circuit.
- (C) 0.5: Incorrect. This value does not apply to purely inductive circuits.
- (D) infinity: Incorrect. This is not a valid power factor value in any circuit.
Step 4: Conclusion.
In a purely inductive circuit, the power factor is 0.