At resonance, the given parallel circuit constituted by an iron - cored coil and a capacitor behaves like

In the given circuit, the voltage $$\overline {{V_L}} $$ has a phase angle of ____________ with respect to $$\overline {{V_S}} .$$

If a two-port network is passive, then we have, with the usual notation, the following relationship

Superposition principle is not applicable to a network containing time-varying registors.