what causes the electrons to drift in the direction of electric field when a battery is connected..(yes,it is the potential difference..but what really happens deep down in the atomic scale in the conductor??)

Question

anonymous · Answer

what is the electrical fields value going to be

anonymous · Answer

also electrons drift in the opposite direction of fields

anonymous · Answer

oh im sorry...yes in the opposite direction...but how does a battery do it?

anonymous · Answer

potential difference is like a kick given to the charged particles.. higher the potential difference, higher the kick they get...

So you first start with a capacitor.. a fully charged capacitor.. it has one plate at a higher potential compared to the other plate.. so when you close the circuit.. maybe connect a bulb in between... the electrons from the lower potential go to the higher potential..to neutralize the charges on each plate... note that the capacitor hasn't lost any charges in process.. and as the electrons go trhough the bulb, they heat it up due to resistance, and thus the bulb starts glowing.. but once the capacitor is discharged, no longer will electrons flow and the bulb stops glowing (this was the principle of flash earlier, and is used in medical defibliators in emergency vans)

now lets come to battery, the only difference between a capacitor (charged) and a battery is that a battery can maintain the potential difference . how?? as it loses one electron from a plate at lower poential(cathode)  and goes to a plate at the higher potential (anode).. internally there is a chemical reaction that takes place, which transfers an electron from anode to cathode back..  and thus the potential difference is maintained.. so ultimately all the chemicals are used up and no longer can reaction take place.. that is when the battery is like a discharging capacitor. and the voltage dims out.. you must have seen.. a battery never stops directly working.. it dims out.. and then slowly stops.. 


at a microscopic level, the electrons never move in a straight line, cause they have kinectic energy associated with them ( i am talking about conduction electrons , not the ones bound to the nucleus ).. so its because of this thermal agitation, they keep drifting .. and hence keep colliding with other electrons and the walls of the crystal lattice.. and thus we have resistance in the first place!!.. I wasn't sure what you really wanted :D

anonymous · Answer

actually what i meant was..when we study abt current electricity we study abt electrons inside the conductor or in the example case say the bulb and the wire..so i was wondering what gives them this kick u said...and then on learning batteries,it was like only the electrons from the battery are moving through the circuit and not the conductor electrons...which is right?

anonymous · Answer

@Mashy

anonymous · Answer

no not really..!! when the battery is in the closed circuit.. it sets up an electric field. This electric field affects all the electrons.. and all conduction electrons start moving .. think of it as an array of electrons.. initially stationary (not really but think of it ).. now when battery is added.. the array is moving .. so all electrons in the line keep moving.. so when you connect a battery to the bulb and switch on, its not that the electrons from the battery SO TO SPEAK have to reach towards the bulb.. and make it glow.. its just that ALLL the electrons now start drifting.. infact the drift speed of electrons is very slow.. so the reason you see the instantaneous effect is cause the field travels very fast.. (don't ask how fast.. that's deep physics involving relativity .. but imagine almost instantaneous ).. so once field is set up.. all electrons start drifting..

vincent-lyon.fr · Answer

All electrons are moving.
It's like a closed pipe full of water in which there is a pump.
The pump changes the pressure and the water flows from higher pressure to lower pressure.

The free electrons constitute a sort of incompressible gas in the conductor, taht behaves like the water in the pipe.

anonymous · Answer

thank u friends...and btw @Mashy i think the field should spread at the speed of light...(nw i got two mangoes in one stone:)...i was long_wondering hw with the drift speed of few mm/s every electrical equipment was operatd so fast..tnk u)