Final answer:
Voltage differences create an electric field that pushes free charges through a conductor, resulting in an electric current. This occurrence is explained by Ohm's Law, which states that current is directly proportional to the voltage applied to a conductor. Conventional current flows from the positive to the negative terminal although electrons, the actual charge carriers in metals, move in the opposite direction.
Step-by-step explanation:
Voltage differences are what drive an electric current in a conductor. When a voltage source such as a battery or a generator is connected to a conductor, it applies a potential difference that creates an electric field. This electric field exerts a force on free charges, causing them to move and create an electric current. In a material like a metal wire, the current is carried by the movement of electrons, which are negative charges moving from the negative terminal to the positive terminal. When discussing current flow, we often refer to the term "conventional current," which flows from the positive terminal to the negative terminal, even though the actual charge carriers (electrons) move in the opposite direction. This stems from historical convention initiated by Benjamin Franklin.
According to Ohm's Law, the current that flows through a substance is directly proportional to the voltage applied to it, which means that a higher voltage will generally result in a larger current, assuming the resistance of the material does not change. If charges accumulate at certain points, reducing the voltage there, the electric field will adjust to push the current toward areas with higher voltage. In static conditions, excess charges collect along the surface of a conductor until static equilibrium is reached.