What is electric current that periodically reverses direction called?

Electric current that periodically reverses direction is known as alternating current, or AC. This type of current flows in one direction for a certain period, then reverses and flows in the opposite direction. Alternating current is commonly used in household power supplies because it is more efficient for transmitting electricity over long distances.

In contrast, the other options do not accurately describe this phenomenon. For example, switching current does not refer to a type of electrical flow; insulating current pertains to materials that do not conduct electricity; and primary current usually refers to the initial current in a circuit or system, rather than to one that changes direction. Thus, alternating current is the most precise and commonly used term for current that reverses direction periodically.