Question

A 30-Volts battery with zero source resistance is connected to a coaxial line of characteristic impedance of 50 Ohms at t = 0 second and terminated in an unknown resistive load. The line length is such that it takes 400 $\mu s$ for an electromagnetic wave to travel from source end to load end and vice-versa. At t = 400 $\mu s$. the voltage at the load end is found to be 40 Volts.

The load resistance is

Answer 1

Ans : (d)


10 V reflects to add to 30 V in phase and gives 40 V


$\Gamma =\frac{V_r}{V_i}=\frac{10}{30}=\frac{1}{3}$

$\Gamma =\frac{Z_L-Z_0}{Z_L+Z_0}$

$\Rightarrow \frac{1}{3}=\frac{Z_L-50}{Z_L+50}$

$\Rightarrow Z_L=100\Omega$