Final answer:
The flow of electricity along a conductor is called (a) an electric current.
Step-by-step explanation:
The flow of electricity along a conductor is called an electric current. This is the movement of electrical charges through a conductor, such as a wire. Electric current can be due to the flow of electrons in electric wires or the flow of cations and anions in electrolytes. The direction of the electric current is conventionally defined as the direction in which positive charges would move in the electric field, which is opposite to the direction of electron flow. The SI unit of electric current is the ampere (A), which is defined as one coulomb (C) of charge passing through a conductor per second (1 A = 1 C/s).
Direct current (DC), as the name suggests, flows in only one direction and is used in many electronic devices. The movement of electric charges in a conductor depends on factors such as the applied voltage, the properties of the material, and the state of the material.
When charges reach a constant velocity within the conductor, known as the 'drift velocity', an electric current is established. This flow is analogous to water moving through a pipe, where we can count the water molecules (or charges in the case of the conductor) that flow past a certain section.