What forces are acting on electron in a circuit?

[Eugene567]

What forces are acting on electron in a circuit?
What is the source of such kind of forces?
Do electrons act on each other in electric current?
If i have an ordinary electric circuit with only one resistor, then if i raise resistance, the electric current goes down. As I understand it happens because the vector E of elecric field inside the conductor goes down. The main question is how electric field (vector E) "feels" that i raised resistance? Well if I have a water flow in a tube i can imagine it. Assume some obstacle suddenly appears in a tube, then it stops the nearest moving molecules of water. This molecules of water stop molecules behind them, which then stops molecules behind them ...etc. And then all molecules are stopped. That's because molecules act on each other. It's like standing in a queue or walking in a crowd. If some man in front of me stops, then I will stop and the man behind of me will stop too. But what about electric current? Is it the same process? Do electrons act each other like molecules of water or like people in a crowd? If it's true that means electric field caused by electrons themself? I'm not only interested about how electric field distributed inside a conductor, I'm interested about the source of that field too.

 

[Gaussian97]

The sources of the field are the electrons themselves. What a battery does is to create electrons by a chemical reaction in the anode and absorb electrons in the cathode. If the two electrodes are connected by a wire, this will make the electrons go from the anode to the cathode, but if you put a resistance in between, this will stop the electrons and reduce the current.

 

[jbriggs444]

Do electrons act each other like molecules of water or like people in a crowd?

Yes. A cloud of free electrons (in a conductive substance that otherwise would have a net positive charge) behaves like an highly incompressible fluid.

If you managed to remove the electrons from a small space, leaving a positively charged void, the positive charge would attract the surrounding electons, filling the void.

If you compressed extra electrons into a small space, creating a negatively charged region, the excess electrons would be repelled, eliminating the concentration.

The electrostatic attraction or repulsion between charged particles is considerable. I once heard that moving one cubic centimeter's worth of electrons from a Saturn V rocket to the launch pad would produce enough electrostatic attraction to prevent the rocket from taking off. That may give some feel for the degree of incompressibility of the electrical "fluid".