Oklahoma Electrical Practice Exam

What does alternating current mean regarding the direction of the flow?

1. It flows continuously in one direction

2. Its direction changes periodically

3. It flows in a spiral motion

4. It is static and does not flow

The correct answer is: Its direction changes periodically

Alternating current (AC) refers to an electric current that reverses its direction periodically. This means that the flow of electric charge changes direction at regular intervals, typically measured in Hertz (Hz). In standard household AC circuits in the United States, this frequency is usually 60 Hz, meaning the current changes direction 60 times per second. This alternating nature allows AC to effectively transmit electricity over long distances with less energy loss compared to direct current (DC), which flows constantly in a single direction. The periodic reversal in the direction of flow is key to the operation of many electrical devices and systems, including motors and transformers, which are designed to utilize AC's characteristics for efficient performance. Understanding this fundamental property of alternating current is crucial for anyone studying electrical systems and their applications.