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An a.c. voltage V=Vm sin ot is applied across an inductor L. Obtain an expression for current I. |
Answer» Solution :When an alternating voltage `V = V_(m)`sin OOT is applied across an inductor L, an alternating CURRENT flows through it and consequently an emf is induced across its ends which is `epsilon = -L (dl)/(dt)`. Thus, in equilibrium `V + epsilon=0`  or `V - L (dl)/(dt) =0` or `L (dl)/(dt) = V = V_(m) sin omega t` `therefore rArr I = V_(m)/L int sin omega t dt = V_(m)/L [(-cos omega t)/(omega)] = V_(m)/(L omega) cos omega t` `I_(m) = V_(m)/(L omega) = V_(m)/X_(L)` and `X_(L) = L_(omega)` is called the inductive REACTANCE of given inductor. |
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