Why is a current induced in a conductor placed in a changing m.field ?

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Discussion Overview

The discussion centers on the phenomenon of current induction in conductors placed in changing magnetic fields or moving conductors. Participants explore the underlying reasons for this induction, particularly at the atomic and electronic levels, while referencing concepts such as the Lorentz force and quantum field theory.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants reference the Lorentz force as a fundamental explanation for the induction of current in conductors within magnetic fields.
  • Others suggest that the relationship between electricity and magnetism is unified under special relativity, indicating that they are different manifestations of the same force.
  • A participant questions the distinction between the "how" and "why" of induction, seeking clarity on whether the "why" can be adequately answered.
  • Some express a desire for a deeper understanding of the atomic-level interactions that occur during induction, specifically how magnetic fields affect free electrons in conductors.
  • One participant introduces the idea that magnetic fields consist of virtual photons that mediate electromagnetic forces, referencing quantum field theory and Feynman diagrams.
  • Another participant mentions that conductors create opposing magnetic fields in response to changes, suggesting a more simplified view of the phenomenon.
  • Further discussion touches on the implications of Maxwell's equations and the conservation of energy in relation to induced currents.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and interest in the mechanisms of induction, with no consensus on the deeper "why" behind the phenomenon. Some agree on the role of the Lorentz force and the relationship between electricity and magnetism, while others seek more detailed explanations that remain unresolved.

Contextual Notes

Participants acknowledge limitations in their understanding of the atomic interactions involved in induction, and there are references to unresolved concepts in quantum field theory and the implications of Maxwell's equations.

B4ssHunter
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the title says it all , why does a changing magnetic field* or a moving conductor * induce a current ?
i know the how , i know how it works ,i know that a changing magnetic field creates a changing electric field , but i want to understand how this works on the electronic level , what is the real reason behind this induction ?
 
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Look up Lorentz force. It covers this.

Claude
 
In simple terms, the Lorentz force. Just like a free moving electron in a magnetic field feels a force, so does a conducting wire (made up of many electrons). Leading on from the Lorentz force, special relativity demands that electricity and magnetism are one in the same, just different manifestations of the same force. Also induction helps conserve energy in a system. If a static magnetic field produced currents in a stationary wire it would violate energy conservation laws.
 
If I may ask the 1st poster a question, (s)he said (s)he knows the answer to the how question, but not the why question.

1st: What's the difference?

2nd: If there is a difference, is the why question answerable?
 
I think the OP KNOWS what happens when you put a wire in a mag field, he/ she just wants a deeper descripton of what's happening on a smaller scale
 
i know what happens and i know how to calculate the emf produced , its just what i really want to know is why or even how that happens at the atomic levels , my textbook says that the field affects free electrons in the conductor , but how does the field affect them ?
 
Yes the magnetic field interacts with electrons. Any charged (positive or negative) particle interacts with magnetic fields. If we look at this from a QFT perspective the magnetic field is made up of (not sure the correct wording here) virtual photons that mediate electromagnetic force. Photon/ electron interaction is depicted by feynman diagrams. I don't think the explanation could get any deeper. You could keep asking why or how but there may not be an answer to that...
 
so i should basically take it as my teacher says , conductors oppose the change in magnetic field by creating their own magnetic fields . that's it right ?
 
The induced current creates an opposing magnetic field in a conducting loop. Like I said in my first post there are some subtle consequences of all this that will only be appreciated through further study of maxwell's equations, namely invariance, conservation of energy etc. QFT would be the next step in a deeper more fundamental understanding of this phenomenon.

Cris
 

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