InterviewSolution
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InterviewSolution
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The current through a coil self inductance L = 2 mH is given by I=t^(2)e^(-1) at time t. How long it will take to make the e.m.f. zero ? |
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Answer» Solution :`I=t^(2)e^(-t)` `therefore (dl)/(dt)=2te^(-t)-t^(2)e^(-t)=te^(-t)(2-t)` The induced emf is `epsilon = -L(dI)/(dt)` ACCORDING to GIVEN problem, `epsilon = 0` `rArr (dI)/(dt)=0 ""` (Since `L ne 0`) or `e^(-t)t(2-t)=0`.Either t = 0 or t = 2 s t = 2 matches with the option (b). |
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