Assuming perfect conductors of a transmission line, pure TEM propagation is NOT possible in

All transmission line sections shown in Fig. have characteristic impedance $${R_0}\, + \,j0$$. The input impedance $${Z_{in}}$$ equals

A transmission line of 50$$\Omega $$ characteristic impedance is terminated with a 100 $$\Omega $$ resistance. The minimum impedance measured on the line is equal to

A lossless transmission line having 50 $$\Omega $$ characteristic impedance and lenght $$\lambda /4$$ is short ciruited at one end and connected to an ideal voltage sourec of 1 V at the other end. The current drawn from the voltage source is