How often does the direction of current flowing through a power line change?

The correct choice indicates that the direction of current flowing through a power line changes 60 times per second, which corresponds to a frequency of 60 hertz (Hz). This is a standard frequency used in North America for alternating current (AC) systems.

In an AC power line, the current oscillates back and forth, meaning it reverses direction periodically. At a frequency of 60 Hz, the current completes one full cycle of direction change in a second, resulting in the current changing directions 60 times (once for each half cycle of the waveform).

This frequency is significant because it is widely used for residential and commercial electrical systems, making it an essential concept for apprentices and professionals in the electrical field. Understanding this helps linemen work safely with the electrical systems they will encounter.