The speed at which electrical current travels through wires is determined by the motion of electric charges, specifically electrons, within the material. It's important to note that the speed of electrical current is not the same as the speed of light. The speed of light in a vacuum is a fundamental constant, approximately 299,792,458 meters per second (m/s), denoted as "c."
In metallic conductors like copper or aluminum, which are commonly used for electrical wiring, the movement of electrons is responsible for carrying the electric current. When a voltage difference (potential difference) is applied across the ends of a conductor, an electric field is established. This electric field exerts a force on the free electrons within the conductor, causing them to drift in the direction of the electric field. However, it's important to understand that the individual electron motion is relatively slow.
The average speed at which electrons move in a typical conductor is significantly less than the speed of light. In fact, it's on the order of millimeters per second (mm/s) or even less. This electron drift velocity is relatively slow, but the effect of the electric field propagates rapidly, leading to the perception that electrical current travels at high speeds.
The reason why electrical current travels more slowly in other materials, such as semiconductors or insulators, is related to their atomic and molecular structures. In these materials, the movement of electrons is more restricted due to stronger interatomic or intermolecular forces. Electrons may be tightly bound to atoms or have limited mobility, resulting in slower overall movement and slower propagation of electrical signals. This is one of the reasons why semiconductors are used for electronic components such as transistors, as their electrical behavior can be controlled by manipulating the movement of charges.
To summarize, while the speed of electrical current is not as fast as the speed of light, it can still propagate rapidly through conductive materials due to the coordinated motion of electrons in response to an electric field. The specific speed of current flow depends on the properties of the material and the forces acting on the charged particles within it.