Ac Circuits

Step 1: Analyze option P (pure resistor)

Impedance is real and there is no phase difference. The current will be in phase with voltage, hence same shape as voltage (sine wave). Matches with graph (3).

Step 2: Analyze option Q (R-L circuit)

In an R-L circuit, current lags voltage. From the graphs, graph (5) shows a lag.

Step 3: Analyze option R (R-L-C circuit)

Resonance occurs when . Given:

Check resonance condition:

Since , the circuit is inductive → current lags slightly. Graph (2) matches this behavior.

Step 4: Analyze option S (R-L-C circuit)

Check for resonance:

Hence, circuit is at resonance → current is maximum and in phase with voltage. Graph (1) shows maximum amplitude and sharp waveform.