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An e.m.f. `E=4cos(1000t)`volt is applied to an `LR` circuit of inductance `3mH` and resistance `4ohm`. The amplitude of current in the circuit isA. 1.0AB. `4/7 A`C. `0.8 A`D. `4/(sqrt(7))A` |
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Answer» Correct Answer - C ` E = 4 cos (1000t)` `:. E_(0) = 4 V and omega = 1000` `:.` inductive reactance `X_(L) = omega L = 1000 xx 3 xx 10^(-3) = 3 Omega` `:.` Impedance `Z = sqrt(R^(2)+X_(L)^(2)) = sqrt(4^(2)+3^(2))=5` `I_(0) = (V_0)/(Z) = 4/5 = 0.8 A`. |
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