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InterviewSolution
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A current of 4 A flows in a coil when connected to a 12 V dc source. If the same coil is connected to a `12 V, 50 rad s^(-1)` ac source, a current of 2.4 A flows of the coil in the circuit. The power developed in the circuit of a `2500 (mu)F` capacitor that is connected in series with the coil isA. 17.28 WB. 8.64 WC. 10 WD. 15 W |
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Answer» Correct Answer - A Now when the capacitor is connected to the above circuit in series, `X_(C)=1/(omega C) = (1)/(50 xx 2500 xx 10^(-6)) =(10^3)/(125) = 8 Omega` so, `Z=sqrt(R^(2)+(X_(L)-X_(C ))^(2)) = sqrt(3^(2)+(4-8)^(2))= 5 Omega` and hence, `I_(rms) = V/Z 12/5 = 2.4 A` so, `P_(av) = V_(rms) I_(rms) cos phi = (I_(rms)xxZ) xx (I_(rms))xx((R )/(Z))` i.e., `P(av)=I_(rms)^(2)R=(2.4)^(2) xx 3 = 17.28 W`. |
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