www A transmission-line system involving two lines. In the system shown in Fig. 6.64, assume that Vg is a constant voltage source of 100 V and the switch S is closed at t = 0. Find and sketch: (a) the line voltage versus z for t = 0.2 μs; (b) the line cur- rent versus z for t = 0.4 μs; (c) the line voltage versus t for z = 30 m; and (d) the line current versus t for z == -40 m. S t=0 120 Ω Zo=12002 vp = 2 × 108 m/s Zo=602 60 Ω vp = 3 × 108 m/s 60 Ω. z=-300 m z=0- z=0+ N z = 300 m www