Postal Study Package $2020$

with List$-$II nd choose en below.

Q$.15$ A two port network having $Z-$parameters $Z_{11},Z_{12}{Z}_{21}$ and $Z_{22}$ is terminated in a load impedance $Z_L$ as shown in the figure. The input impedance $Z_{in}$ of the two port network is given by

$($a$)Z_{11}-\frac{Z_{12}{Z}_{21}}{(Z_{22}+Z_L)}$

$($b$)Z_{11}-\frac{Z_{12}(Z_{21}+Z_L)}{Z_{22}}$

$($c$)Z_{11}+Z_L$

$($d$)Z_{22}+Z_L$