NCERT Physics Class 12 Exemplar Ch 7 Alternating Current Part 2

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18 In series LCR circuit, the plot of is shown in Figure. Find the bandwidth and mark in the figure.

LCR circuit- I(max )- Find bandwidth

LCR Circuit- I(max )- Find Bandwidth


  • Bandwidth corresponds to frequencies at which.

  • It is shown in the Fig.

LCR circuit- plot of I(max )

LCR Circuit- Plot of I(max )

19 The alternating current in a circuit is described by the graph shown in Figure. Show rms current in this graph.

Alternating current rms graph

Alternating Current Rms Graph


(Shown in Fig. by dotted line)

Alternating current described by the graph

Alternating Current Described by the Graph

20 How does the sign of the phase angle , by which the supply voltage leads the current in an LCR series circuit, change as the supply frequency is gradually increased from very low to very high values.


  • From negative to zero to positive; zero at resonant frequency

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