Question

The power factor of an $AC$ circuit having resistance $R$ and inductance $L$ connected in series and an angular velocity $\omega$ is

• A. $R / \omega L$
• B. $R /\left(R^{2}+\omega^{2} L^{2}\right)^{1 / 2}$
• C. $\omega L / R$
• D. $R /\left(R^{2}-\omega^{2} L^{2}\right)^{1 / 2}$

Answer 1

Answer: (B)

$\cos \phi=\frac{R}{Z}=\frac{R}{\left(R^{2}+\omega^{2} L^{2}\right)^{1 / 2}}$