If the voltage at the earth's connection point is 20 kilovolts, what is the surface voltage measured at a distance of nine feet away?

To determine the surface voltage measured at a distance of nine feet from a point with a voltage of 20 kilovolts, it's essential to understand how voltage diminishes with distance in a grounding context.

The phenomenon at play is known as the inverse square law related to electric fields, where the potential voltage decreases as the distance from the source increases. This means that voltage does not stay constant but rather diminishes over distance due to the distribution of electrical charge in the environment.

In this scenario, the correct answer indicates that at a distance of nine feet from the source of 20 kilovolts, the surface voltage is measured at 2.5 kilovolts. This value reflects how much the voltage decreases in relation to the distance from the high-voltage earth connection point.

To arrive at this understanding, calculations involving the geometric properties related to the electric field can be applied, which usually results in a fractional voltage at given distances. The specific measurement of 2.5 kilovolts suggests a calculated reduction based on parameters of distance and voltage drop.

The other options—5 kilovolts, 1 kilovolt, and 10 kilovolts—represent different potential surface voltages that do not accurately reflect the expected decrease in voltage over that