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| 1. |
Explain why the reactance offered by an inductor increases with increasing frequency of an alternating voltage. |
| Answer» SOLUTION :We know that an inductor opposes flow of current through it by developing an induced emf in back direction in accordance with Lenz.s law. The induced voltage has a polarity so as to maintain the current at its PRESENT value. If the current is decreasing, the induced emf tends to increase the current and vice versa. As the magnitude of induced emf is proportional to the rate of CHANGE of current, it will provide greater reactance to the flow of current of rate of change of current is faster that is the frequency of a.c. is more. THEREFORE, the reactance offered by an inductor increases with increasing frequency of an alternating voltage. In fact it is given by `X_(L) = Lomega = 2pi v`. | |