What is a characteristic of alternating current?

Alternating current (AC) is characterized by its ability to change direction periodically. Specifically, in the United States, the frequency of AC is typically 60 hertz, which means the current changes polarity 60 times per second. This property allows AC to efficiently transmit power over long distances and makes it suitable for residential and commercial power supplies.

In contrast, direct current (DC) flows consistently in one direction, which is a key difference from AC. Additionally, alternating current is not limited to residential settings; it is widely used in various applications, including industrial and commercial contexts. Voltage levels of AC can be higher or lower than those of DC; this depends on the specific application and requirements. Therefore, the statement regarding polarity change accurately describes a fundamental aspect of alternating current.