"Does electric current move at the speed of light?"
We know that electromagnetic waves travel at the speed of light. Current does not travel at the speed of light. Electrons that make up the current travel at significantly less than the speed of light (in fact, typically only a few cm/s in a conductor carrying electricity). So one would ask "Why then does a light appear to turn on immediately when plugged in through a 100 metre extension cord?" To understand this a tube and marble analogy can be looked at. Consider a 100 metre tube whose inside diameter is slightly larger than a marble. This tube is filled end to end with marbles. If one additional marble is inserted at one end of the tube, a marble immediately falls out of the other end of the tube so the effect of the "marble current" is almost instantaneous (i.e. the effect travels 100 metres in almost no time and yet the marbles themselves have hardly moved). This is effectively what happens in a conductor where you force electrons into one end of a conductor and the effects of the electrons ripple down much like the marbles in the tube. This effect is almost instantaneous (although still slower than the speed of light).