Question

The intrinsic impedance of free space is (a) 489 (b) 265 (c) 192 (d) 377 The question was asked in homework. My enquiry is from Plane Waves in Free Space topic in portion EM Wave Propagation 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

Right answer is (d) 377 To explain: The intrinsic impedance is the square root of ratio of the permeability to the permittivity. In free space, the permeability and the permittivity is same as the absolute permeability and permittivity respectively. This is due to unity permeability and permittivity in free space. Thus η = √(μ/ε), where absolute permeability is given by 4π x 10^-7 and absolute permittivity is given by 8.854 x 10^-12. The intrinsic impedance will be 377 ohms.