In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value: (a) The bandwidth of resonance circuit will increase. (b) The resonance frequency will increase. (c) The quality factor will increase. (d) The quality factor and the resonance frequency will remain constant.

Answer: (a). ω₀ = (1)/(√(LC)) does not depend on R, so the resonance frequency is unchanged. Bandwidth = R/L increases as R increases. Q = (ω₀ L)/(R) decreases as R increases. So the answer is (a) the bandwidth will increase.

In a series LCR resonance circuit, if we change the resistance only… | JEE Main 2021 (18 Mar, Shift 1)

Q89JEE Main 2021 · 18 MAR · SHIFT 1Easy

Resonance, Bandwidth & Q Factor

In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value:

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Answer: (a)

$\omega_0 = \frac{1}{\sqrt{LC}}$ does not depend on $R$ , so the resonance frequency is unchanged.
Bandwidth $= \frac{R}{L}$ increases as $R$ increases.
$Q = \frac{\omega_0 L}{R}$ decreases as $R$ increases.
So the answer is (a) the bandwidth will increase.

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Resonance, Bandwidth & Q Factor question from JEE Main 2021 (18 Mar, Shift 1)

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