Question

The input impedance of a quarter wave line 50 ohm and load impedance of 20 ohm is (a) 50 (b) 20 (c) 1000 (d) 125 The question was asked during an online exam. This is a very interesting question from Input and Characteristic Impedances in portion Transmission Lines 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 option is (d) 125 Easiest explanation: The characteristic impedance will be the geometric mean of the input impedance and the load impedance. Thus Zo^2 = Zin ZL. On substituting for Zo = 50 and ZL = 20, we get the input impedance as 50^2/20 = 125 ohm.