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suppose the resonance frequency of the LCR series circuit is fr. Will the current in the circuit lag behind the voltage or lead the voltage in the following cases :

(i) when the applied AC frequency f > fr

(ii) when f < fr

we can say that the current lags behind the voltage when the circuit in inductive. The phase angle can be calculated by [tex]\tan\phi=\frac{X_{L}-X_{C}}{R}[/tex] . But how can we conclude whether XL - XC is postive or not when we are given the applied frequency.

I was able to figure out one thing. When the applied frequency is same as the resonance frequency, XL = XC , which means [tex]\tan\phi=0[/tex]. so the current and voltage are in phase.

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# Homework Help: LCR series circuit

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