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A coil of inductance `300mh` and resistance `2Omega` is connected to a source of voltage `2V`. The current reaches half of its steady state value inA. `0.05 s`B. `0.1 s`C. `0.15 s`D. `0.3 s` |
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Answer» Correct Answer - B The current at any instant is given by `l=l_(0)(1-e^(-Rt//L))` `l_(0)/2=l_(0)(1-e^(-Rt//L))` `1/2=(1-e^(-Rt//L))` `e^(-Rt//L)=1/2` `(Rt)/L=n2` `therefore t=L/R "ln" 2` `=(300 xx 10^(-3))/2xx0.693 =150xx0.693xx10^(-3)` `=0.10395 sec =0.1 sec` |
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