My text book says in absense of electric field electros moving in one direction is equal to electrons moving in opposite direction to mantain the neutral state of the conductor. But in another book I read this topic and according to it fre electron in absense of electric field move toward positive terminal of battery. Anyone explain this?
1 Answer
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You applying the same logic to both scenarios, but the two systems aren't physically equivalent.
Situation 1: You state that in the absence of an electric field electrons on the surface of the conductor will always configure themselves to render $V=constant$ on the surface of the conductor. Meaning that in the absence of an electric field there will be no measurable electric field emanating from the conductor (as it should be).
Situation 2: You say that a "free electron" will always move forward the positive terminal of a battery. While it's true that the electron does move towards a positively charged terminal, it is not true that once you apply a voltage to influence the electron that the electron is "free" in any real sense. "free" by definition means that there is no potential that affects its motion, which is just simply not the case in this situation. In this situation there is an electric field applied since you are applying a nontrivial potential.
answered Dec 26, 2018 at 2:19
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$\begingroup$ Hi by "free" do you mean valance electron which occupy the outermost shell and it requires less energy to kick out? $\endgroup$– user6760Commented Dec 26, 2018 at 4:56
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$\begingroup$ Electrons on the surface on a conductor are free to move around.. I’m talking about those guys $\endgroup$ Commented Dec 26, 2018 at 5:04