A coil of resistance and either pure inductance or pure capacitance is connected in…
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A coil of resistance R and either pure inductance or pure capacitance is connected in series to an AC source.
(i) Define the term "impedance" of a series AC circuit and write its mathematical form for (a) an R–L circuit, (b) an R–C circuit.
(ii) Qualitatively explain how the rms current in a series R–L circuit is affected when the supply frequency is doubled, keeping the source voltage amplitude and circuit constants unchanged.
(iii) State, with reason, whether the rms current in a series R–C circuit will increase or decrease when the supply frequency is doubled under the same conditions.
(iv) From your discussion above, comment on whether each type of circuit behaves predominantly resistive, inductive, or capacitive at very high frequencies.