Q120 / 180 · NEET 2016 (Phase 2) · Physics

The potential differences across the resistance, capacitance, and inductance are $80 V, 40 V$ and $100 V$ , respectively in an LCR circuit. The power factor of this circuit is

Solution

$P_{ac} = V_{rms} I_{rms} \cos (ϕ)$ ,

where, $\cos (ϕ)$ is the power factor.

$cosϕ = \frac{R}{z} = \frac{V_{R}}{V} = \frac{80}{\sqrt{80^{2} + {(100 - 40)}^{2}}}$

$= \frac{80}{100} = 0.8$ .

where, $Z$ is the impedence of the circuit.

Hence, the correct answer is option: 'C'.