Magnetic Field generated by a wire

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Discussion Overview

The discussion revolves around the generation of magnetic fields by electric currents in wires, exploring the underlying properties and mechanisms that lead to the existence of these fields. Participants seek clarification on concepts such as magnetic moments and the relationship between electric charge motion and magnetic field production.

Discussion Character

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

Main Points Raised

  • One participant questions how magnetic fields are produced, suggesting they cannot simply arise from current in a wire without an underlying mechanism.
  • Another participant references the magnetic moment being due to the motion of electric charges and the intrinsic magnetism of elementary particles, seeking clarification on these terms.
  • A different participant asserts that current densities, including both linear and quantum motion of charges, are responsible for magnetic fields.
  • One participant introduces a relativistic perspective, stating that the perception of the magnetic field depends on the observer's frame of reference, which raises questions about the nature of magnetic fields.
  • A participant parallels the discussion of magnetic fields with electric fields, arguing that both fields are postulated in classical electrodynamics without a defined mechanism for their existence.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and interpretation of the concepts involved, with no consensus reached on the underlying mechanisms of magnetic field generation or the definitions of key terms like magnetic moment and intrinsic magnetism.

Contextual Notes

Participants highlight limitations in their understanding of complex concepts, such as the relationship between electric charge motion and magnetic field production, and the absence of a clear mechanism in classical electrodynamics as described by Maxwell's equations.

Who May Find This Useful

This discussion may be useful for students and individuals interested in the foundational concepts of electromagnetism, particularly those seeking to understand the relationship between electric currents and magnetic fields.

Ravui
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So my notes detail how to find the direction of the magnetic field (right-hand grip rule), but how exactly are these magnetic fields produced? They can't just spontaneously come into existence just because there is a current through a wire, right? What properties allow them to come into being?
 
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I checked up wiki already and came across this :

The magnetic moment is due to

(1) motion of electric charges, such as electric currents, and (2) the intrinsic magnetism of elementary particles, such as the electron.

I don't exactly understand what is i)the magnetic moment and ii)the intrinsic magnetism.

Oh and one more thing, is the 'motion of electric charges' referring to the electron spin?

I'm grade 12 so I'd appreciate it if someone would explain it in terms I'd understand.

Thanks :)
 
Well you kind of already nailed it. Current densities are responsible for the magnetic field. Both [tex]J[/tex] and [tex]\dot{J}[/tex]. The motion of charges, linear motion, spinning ( quantum and angular), and periodic all produce magnetc fields.
 
As we know from relativity, If a electron is in your rest frame, and I am moving towards that electron, then you will NOT fell the magnetic field, and I WILL. Strange? then you may start to understand what is magnetic field..
 
Ravui said:
how exactly are these magnetic fields produced? They can't just spontaneously come into existence just because there is a current through a wire, right?

For that matter, how exactly are electric fields produced? They can't just spontaneously come into existence just because there is a charge located somewhere, right? :wink:

In both cases, the existence of the field is a postulate of classical electrodynamics. Maxwell's equations tell us the relationships between fields, charges and currents, but do not include an underlying mechanism.
 

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