An AC (220 V, 50 Hz) circuit has a resistance of \( 3\,\Omega \) and an impedance of \( 5\,\Omega \). The power factor of the circuit will be:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 0.6
The power factor of an ac circuit is \( \cos\phi = \frac{R}{Z} \), the ratio of the resistance to the impedance.
\( \displaystyle \cos\phi = \frac{R}{Z} = \frac{3\,\Omega}{5\,\Omega} = 0.6 \)
The voltage and frequency are not needed. A power factor is a cosine and cannot exceed 1, so Options (1) and (4) are impossible, and a value of zero would need \( R = 0 \).