Alternating Current

JEE Main level, single correct, medium

62 of 190

Question 62 of 190

A series LCR circuit is connected to an alternating source of emf E. The current amplitude at resonant frequency is I0I_0. If the value of resistance R becomes twice of its initial value then amplitude of current at resonance will be

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Answer: (C) I02\frac{\mathrm{I}_0}{2}

Initially, I0=εmR\mathrm{I}_0=\frac{\varepsilon_{\mathrm{m}}}{\mathrm{R}}
Finally, I01=εm2R=I02\mathrm{I}_0^1=\frac{\varepsilon_{\mathrm{m}}}{2 \mathrm{R}}=\frac{\mathrm{I}_0}{2}

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