Q 12-07-041JEE MainJEE Main 2026 (24 Jan, Shift 1)Easy
For the series LCR circuit connected with $220\ \text{V}, 50\ \text{Hz}$ a.c source as shown in the figure, the power factor is $\dfrac{\alpha}{10}$. The value of $\alpha$ is ______ .
Answer: (C) 6
$$Z = \sqrt{R^2 + (X_C - X_L)^2} = \sqrt{60^2 + 80^2} = 100\ \Omega$$
$$\cos\phi = \frac RZ = \frac{60}{100} = \frac{6}{10}\Rightarrow\alpha = 6$$
Solution by Sreeraj P, M.Sc Physics