Final answer:
The total voltage at the midpoint of a transmission line, between points with electric fields of 600 V/m and 350 V/m, is approximately 440 V/m. High voltage is used in transmission lines to minimize power losses.
Step-by-step explanation:
The question is about calculating the electric field at the midpoint of a transmission line. We are given that the electric fields at points A and B on the transmission line are 600 V/m and 350 V/m, respectively. Considering that electric field isolines would be denser at A than at B and spread out evenly from A to B, the electric field at the midpoint would be a value between the two. Given the arc length of 13.5 cm for the midpoint, the electric field is calculated to be approximately 440 V/m.
Additionally, the context suggests that long-distance transmission lines are typically kept at high voltages, often in the hundreds of kilovolts range, such as 200 kV or 400 kV, to reduce power losses. The figure of 480 V mentioned is noted as an unreasonably low voltage for long-distance transmission.