Question

The average power absorbed by an impedance Z = 30 – j 70 Ω when a voltage V = 120∠0° is applied is _____________ (a) 35 (b) 37.24 (c) 45 (d) 50.25 This question was addressed to me during an online interview. Origin of the question is Advanced Problems on Magnetically Coupled Circuits topic in chapter Resonance & Magnetically Coupled Circuit of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

Right choice is (b) 37.24 To explain: The current through the impedance is given by, I = \frac{V}{Z} = \frac{120∠0°}{30-j70} = \frac{120∠0°}{76.16∠-66.8°} = 1.576∠66.8° A The average power is, P = 0.5VmImcos (θv – θi) = 0.5(120) (1.576) cos (0 – 66.8°) = 37.24 W.