NEET Physics Alternating Current Questions Solved


2 uF capacitor, 100 Ω resistor and 8 H inductor are connected in series with an AC source.

(i) What should be the frequency of the source such that current drawn in the circuit is maximum?

     What is this frequency called ?

(ii) If the peak value of e.m.f. of the source is 200 V, find the maximum current.

(iii) Draw a graph showing variation of amplitude of circuit current with changing frequency of applied 

      voltage in a series LRC circuit for two different values of resistance R1 and R2 R1>R2.

(iv) Define the term 'Sharpness of Resonance'. Under what condition, does a circuit become more

      selective ?                                                                                                   (5 marks)

(i)    ω0=1LC=18×2×10-6=250 rad/s or f0=ω02π=125πHz                          (1 marks)

        Resonant frequency                                                                                 12 marks


(ii)    Imax=V0R=200100A=2A                                                                             (1 marks) 




                                                    (1 marks)  


(iv)   ω02ω is measure of sharpness of resonance, where ω0 is the resonant frequency and 2ω is

         the resonant frequency and 2ω is the bandwidth.                                           (1 marks)  

          Circuit is more selective if it has greater value of sharpness/The circuit should have smaller 

          band width ω.                                                                                        12 marks

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