question_answer 51)

  Explain why the reactance offered by an inductor increases with increasing frequency of an alternating voltage.

Answer:

                  An inductor opposes flow of current through it by developing a back emf in itself. As per Lenz's law, the induced emf opposes both, the increase and decrease of current. As the induced emf is proportional to the rate of change of current, it will provide greater reactance to the flow of current if the rate of change of current is faster, i.e., if the frequency is higher. Hence, the reactance of inductor is directly proportional to the frequency of a.c. supplied. Mathematically,