Question

How alternating current pulls electrons from neutral in another half cycle?

Answer 1

Think of a wire as a long tube stuffed with electron “balls” connected to each other with very short springs. If you push a ball into one end of the tube, a short time later a ball will protrude from the other end of the tube. This is very much like electron current flow in wires, though in a real wire there are millions or billions (or more) of these “tubes” of electron “balls” connected by their intersecting electrical fields. AC current flows because an AC generator is increasing/decreasing the electrical potential energy of the electrons at one end of the wire, and this provides the “push” (or pull) that propagates very quickly to the other end of the wire. In addition there is long-term drift of electrons back and forth through the wire, but this drift is very slow especially when compared to the velocity of propagation.

Because the pulling and pushing of electrons due to AC current is usually equal in both directions over one complete cycle, the net motion of charges is zero. But because these charges are in motion they are able to do useful work for us.