Question

Find the energy of a coil of inductance 18mH and current passing through it 1.25A.(in 10^-3 order) (a) 14.06 (b) 61 (c) 46.1 (d) 28.12 The question was posed to me in an international level competition. Question is from Magnetostatic Properties in portion Magnetostics of Electromagnetic Theory Select the correct answer from above options Electromagnetic Theory questions and answers, Electromagnetic Theory questions pdf, Electromagnetic Theory question bank, Electromagnetic Theory questions and answers pdf, mcq on Electromagnetic Theory pdf,electromagnetic theory book pdf,electromagnetic theory pdf notes,electromagnetic theory lecture notes,electromagnetic theory of light,maxwell electromagnetic theory,electromagnetic theory proposed by,electromagnetic theory engineering physics,electromagnetic theory nptel

Answer 1

Correct answer is (a) 14.06 Easiest explanation: The magnetic energy possessed by a coil is given by E = 0.5 x LI^2. Put L = 18 x 10^-3 and I = 1.25, thus we get E = 0.5 x 18 x 10^-3 x 1.25^2 = 14.06 x 10^-3 units.