A parallel combination of pure inductor and capacitor is connected across a source of alternating e.m.f. 'e'…

A parallel combination of pure inductor and capacitor is connected across a source of alternating e.m.f. 'e'. The currents flowing through an inductor and capacitor are $i_{L}$ and $i_{C}$ respectively. In this parallel resonant circuit, the condition for currents $i$, $i_{L}$ and $i_{C}$ is ( $i=$ net $\mathrm{r}$.m.s. current in the circuit)
  1. $i \doteq 0, i_{L}=i_{C} \neq 0$
  2. $i \neq 0, i_{L}=i_{C}=0$
  3. $i \doteq i_{L}=i_{C}$
  4. $i \doteq 0, i_{L} \neq i_{C}$

Solution

In parallel resonant circuit, the capacitive and inductive reactance are equal, hence currents are equal but $180^{\circ}$ out of phase with each other. The net current is zero. $\therefore \mathrm{i}=0, \mathrm{i}_{2}=\mathrm{i}_{\mathrm{c}} \neq 0$

Asked in: MHT CET 2020 (12 Oct Shift 1)

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