question_answer 33)

    As the frequency of an ac circuit increases, the current first increases and then decreases. What combination of circuit elements is most likely to comprise the circuit ? (a) Inductor and capacitor (b) Resistor and inductor (c) Resistor and capacitor (d) Resistor, inductor and capacitor.

Answer:

     (a,d)The impedance of an LCR circuit is given by                                              The variation of with is as shown in Fig. 4(EP).23. As increases, Z decreases current increases. At  =  Z is minimum, current is maximum. Beyond  =  Z increases and current decreases. Hence, the circuit elements likely to comprise the circuit are L and C or R, L and C. Choices (a) and (d) are correct.