In an AC (alternating current) circuit, the speed at which electrons physically move through a wire is relatively slow, despite the high frequency of the alternating current. The reason for this is that in an AC circuit, electrons oscillate back and forth rather than moving in a unidirectional flow.
The movement of electrons in a wire is known as drift velocity. The drift velocity is determined by the electric field applied to the wire, which is created by the alternating voltage source. The drift velocity is typically very slow, on the order of millimeters per second.
However, it's important to note that even though the drift velocity is slow, the electrical signal itself, which carries the energy and information, travels at a much higher speed. This signal, known as the electrical wave, travels at nearly the speed of light in the wire, which is approximately 299,792,458 meters per second in vacuum. In a wire, the signal propagates slightly slower due to the effects of the wire's material and electromagnetic properties.
To summarize, while the actual movement of electrons through a wire in an AC circuit is slow, the electrical signal that carries energy and information travels at a much higher speed, approaching the speed of light.