Past exam of the physics course of the year 1 of the natural sciences course of the University of Cambridge / 2024 / Paper 1 / Section A / 2 / Solution

Using the convention $e^{i\omega t}$, the series RLC circuit has complex impedanceAt the stated frequency, $\omega L=180.956\Omega$ and $1/(\omega C)=88.4194\Omega$. ThusThe vector is $(525,92.5)$ in the resistance–reactance plane. Positive reactance means that the net circuit is inductive and current lags voltage. With the alternative $e^{-i\omega t}$ convention the imaginary signs reverse, while the magnitude and physical phase relationship agree.