Question

The energy stored in the magnetic field at a solenoid 100 cm long and 10 cm diameter wound with 1000 turns of wire carrying an electric current of 10 A, is ___________ (a) 1.49 J (b) 0.49 J (c) 0.1 J (d) 1 J This question was posed to me in unit test. The origin of the question is Advanced Problems on Millman’s Theorem and Maximum Power Transfer Theorem in chapter Useful Theorems 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 answer is (b) 0.49 J The explanation: L = \frac{N^2 μ_0 A}{l} = \frac{10^6.4π.10^{-7}.\frac{π}{4}.(100 X 10^{-4})}{1} = \frac{π^2 X 10^{-3}}{1} Energy = 0.5 LI^2 = 0.49 J.