The correct answer is: A. Surge impedance of the line.
Surge impedance is the ratio of the voltage to the current when a surge travels along a transmission line. It is a complex number, and its magnitude is the square root of the ratio of the line impedance to the shunt admittance.
The line impedance is the total impedance of the transmission line, and it is composed of the resistance, inductance, and capacitance of the line. The shunt admittance is the total admittance of the transmission line, and it is composed of the conductance and susceptance of the line.
The surge impedance of the line is a very important parameter, and it is used to design and analyze transmission lines. It is also used to calculate the reflection coefficient at the end of a transmission line.
The other options are incorrect.
- Option B, Conductance of the line, is the reciprocal of the resistance of the line. It is a measure of how easily current can flow through the line.
- Option C, Regulation of the line, is a measure of how much the voltage at the load end of the line changes when the load current changes. It is a dimensionless number, and it is usually expressed as a percentage.
- Option D, None of the above, is incorrect.