Current that flows in only one direction is known as:

Direct current (DC) refers to the flow of electric charge that moves in only one direction. This characteristic distinguishes it from alternating current (AC), which reverses direction periodically. In practical applications, DC is used in various devices such as batteries, solar panels, and electronic circuits where a steady and consistent flow of electricity is required.

Direct current is essential for powering sensitive electronic components where fluctuations in voltage could lead to malfunctions or damage. Additionally, batteries deliver power in the form of direct current, providing a reliable source of energy for portable devices. This steady nature of direct current makes it critical in both industrial and consumer electronics.

Alternating current, while essential for power distribution, involves a back-and-forth flow that is not compatible with all devices and applications. Static current and impulse current refer to other electrical phenomena that do not consistently flow in one direction or have different characteristics and uses altogether. Thus, the answer of direct current accurately captures the definition of a current flowing in one direction.