The characteristic impedance of a transmission line is not known. To determine it, it is suggested to measure the short and open impedances at a point on the line; that is, the load is shorted and the impedance at a point on the line is measured. Then, the load is disconnected (open line) and the impedance at the same point on the line is again measured. These measurement give an open line impedance of -j50 and a shorted line impedance ofj75. Calculate the characteristic impedance of the line.