In an RLC series circuit, which is connected to a source of emf $\varepsilon$_mcos( $ \omega $t), the current lags the voltage by 45$\degree$ if: A) R = 1/ $ \omega $C - $ \omega $L B) R = 1/ $ \omega $L - $ \omega $C C) R = $ \omega $L - 1/ $ \omega $C D) R = $ \omega $C - 1/ $ \omega $L E) $ \omega $L = 1/ $ \omega $C

Question

Quizplus · Accepted Answer

In an RLC circuit, the phase angle φ between the current and voltage is given by tan(φ) = (XL - XC) / R, where XL = ωL and XC = 1/(ωC). For the current to lag the voltage by 45°, tan(45°) = 1, so XL - XC = R. Therefore, R = ωL - 1/(ωC).

In an RLC Series Circuit, Which Is Connected to a Source