NEET Physics Alternating Current Questions Solved

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The figure shows a series LCR circuit with L = 5.0 H, C = 80 µF, R = 40 Ω connected to a variable frequency 240 V source. Calculate

(i) The angular frequency of the source which drives the circuit at resonance.

(ii) The current at the resonating frequency.

(iii)The rms potential drop across the capacitor at resonance.                                    3mark

(i) ω=1LC                                                                                          1/2mark

15×80×10-6=50radian/s                                                               1/2mark

(ii) Current at resonance

Irms=VrmsR=24040A=6A                                                                      (1/2,1/2)mark

(iii) Vrms across capacitor

Vrms = IrmsXc                                                                                        1/2mark

        = 6×150×80×10-6V

       =6×1064×103V=60004V=1500V                                                        1/2mark

Difficulty Level:

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