Question

A relay coil having voltage of magnitude 210 V and frequency 50 Hz is connected to a 210 V, 50 Hz supply. If it has resistance of 50 Ω and an inductance of 0.2 H, the apparent power is _____________ (a) 549.39 VA (b) 275.6 VA (c) 157 VA (d) 187 VA I had been asked this question during an interview. Origin of the question is Problems Involving Standard Time Functions in portion Application of the Laplace Transform in Circuit Analysis 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

The correct choice is (a) 549.39 VA Explanation: Z= 50 + j (0.2) (2π) (50) = 50 + 62.8 S = \frac{|V|^2}{Z} = \frac{210^2}{50 – 62.8} Apparent Power |S| = \frac{210^2}{\sqrt{50^2 + 62.8^2}} = 549.39 VA.