Question

The characteristic impedance of a line having open and short impedances of 20 and 5 respectively is

(a) 20

(b) 100

(c) 25

(d) 10

The question was asked in my homework.

This is a very interesting question from Transmission Lines in division Transmission Lines of Electromagnetic Theory

Answer 1

The correct option is (d) 10

The explanation: The characteristic impedance is the geometric mean of the short and open circuit impedance. It is given by Zo^2 = Zsc Zoc. On substituting Zoc = 20 and Zsc = 5, we get Zo^2 = 20 X 5 = 100. Thus Zo = 10 ohm.