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Alternating Current

Question
CBSEENPH12040128

An inductor 20 mH, a capacitor 100 µF and a resistor 50 Ω are connected in series across a source of emf, V = 10 sin 314 t. The power loss in the circuit is

  • 0.79 W

  • 0.43

  • 1.13

  • 2.74 W

Solution

A.

0.79 W

Power dissipated in an LCR series connected to an a.c source of emf E

P = Ermsirms cosϕ = E2rmsRZ2 = Erms2 RR2+ωL-1Cω2=1022 x 50(50)2 +314 x 20 x 10-3 - 1314 x 100 x 10-62solving we get, P = 0.79 W