What is the difference between alternating current (AC) and direct current (DC)?

The correct choice highlights a key characteristic of alternating current (AC) and direct current (DC). AC is defined by its ability to change direction periodically, which means the flow of electric charge alternates back and forth. This is the type of current typically used in household outlets and power distribution systems because it is more efficient for transporting electricity over long distances.

On the other hand, direct current flows in a single, constant direction. This type of current is commonly found in batteries and electronic devices, where a stable and unidirectional flow is required for proper functioning.

Understanding the fundamental difference between these two types of current is crucial, as they have distinct applications and implications for electric circuits in both residential and commercial use.