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Its true that there is a non zero field (in fact,a field of the magnitude of counter electric field inside the battery used) within a current carrying IDEAL wire (unlike static condition). Thus there should also be non zero potential difference along the wire which says that electron flowing should lose potential. But all electronics is based on the fact that no energy is dissipated in conducting wire. Isn't it a HUGE contradiction??

Details of my doubt: Anyway isn't it true that a conductor will have electron motion inside it when external electric field is introduced in order to be in equilibrium (or to have zero net field inside it). And during the course of movement of electrons there will be non zero field inside the conductor (It’s this field that is being nullified). This is a DEFINING property of conductors. And here's how I see current ----> When a battery is connected in conducting wire,electrons move to be in equilibrium (by its property). But a battery's action is to get the moved electrons from wire's side connected to positive terminal (for attaining equilibrium) back to the side of wire where negative of battery is connected. Thus its prevented from attaining equilibrium. So there exists a non zero electric field (I also think it has the same constant electric field as the counter field of the battery used). And isn't it through this wire (where there's a field) the electrons move to constitute current. So shouldn't it lose potential energy derived from battery? That is, the energy obtained from battery will be used up in the wire itself right (instead of in a resistor as heat)!!

Qmechanic
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vivi
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3 Answers3

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Its NOT true that there is a non zero field within a current carrying IDEAL wire. If we have an ideal wire, the resistance is zero so the voltage is zero hence the field is zero too.

Kashmiri
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If the wire has resistance, then a field is required to maintain current flow.

R.W. Bird
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Its true that there is a non zero field(in fact,a field of the magnitude of counter electric field inside the battery used) within a current carrying IDEAL wire(unlike static condition).

Actually, it is not true. For an ideal wire there is no voltage across the wire regardless of the current through the wire. Of course, real wires have a small resistance, so real wires do have a non zero field. An ideal wire is the limit of a real wire as the wire’s resistance goes to 0. With resistance of 0 there is no voltage regardless of the current, per Ohm’s law.

Isn't it a HUGE contradiction??

No, it is a small approximation.

Anyway isn't it true that a conductor will have electron motion inside it when external electric field is introduced in order to be in equilibrium( or to have zero net field inside it).And during the course of movement of electrons there will be non zero field inside the conductor(Its this field its being nullified).This is a DEFINING property of conductors.

If you take this as the defining property of conductors then an ideal wire is not a conductor, by definition. This may not be the best definition of a conductor. The rest of your confusion seems to stem from this incorrect definition and the associated “nullification” concept.

A more common definition of a conductor is “a conductor is an object or type of material that allows the flow of charge (electrical current) in one or more directions”. No assertion of any relationship between the current and any electric fields is made. In the case of an ideal wire the electric field is zero and the voltage is constant regardless of the current.

Dale
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