Past exam of the physics 2 paper of the University of Oxford / 2018 / 9 / Solution

For this question use phasors with time factor $e^{i\omega t}$, so an electrical impedance is $Z=\tilde{V}/\tilde{I}$. The same electric current flows through all components of a series circuit, and their voltages add by Kirchhoff's voltage law. Hence the total series electrical impedance isThe individual steady sinusoidal currents and their phase relations are derived in the following three parts. The diagram normalizes each current by its own amplitude, so it compares phase differences without mixing unlike physical units.