A Magnetic Misconception on Divergence 0/Closed Field Lines?

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Discussion Overview

The discussion revolves around the relationship between closed magnetic field lines and the concept of work done by magnetic forces. Participants explore whether the presence of closed magnetic field lines implies that no net work can be done by magnetic forces, and they draw comparisons to electric fields and their behavior.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions if it is a misconception to attribute zero work done by magnetic forces to the closed nature of magnetic field lines, suggesting that this might not hold true.
  • Another participant asks for clarification on what is meant by work done by a magnetic force, specifically in relation to electric charges.
  • A participant recalls that electric charges are the primary focus when discussing work done by magnetic forces, referencing Griffith's book.
  • Another participant introduces the concept of an idealized electric dipole, noting that it has closed field lines but can still do work on a charge, challenging the initial premise.

Areas of Agreement / Disagreement

Participants express differing views on whether closed field lines necessarily imply no net work can be done, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

The discussion highlights potential limitations in understanding the implications of closed field lines in both magnetic and electric contexts, as well as the need for clarity on the conditions under which work is defined.

walkeraj
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Question: Can we ultimately atttribute no work or net zero work done by a magnetic force to the closed magnetic field lines that results in Divergence zero of a magnetic field? That is, is it a misconception to say that closed magnetic field lines imply magnetic force will always result in no net work?

(I meant misconception on my part not theory.)

Edit: Why misconception? Now switch to electric field. The field lines between two opposite electric test charges are also closed and resemble that of a bar magnet, though electric in nature. Does it hold? Is it enough to say that since the field lines are closed between the two test charges that no net work can ever be done?
 
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Work done by a magnetic force on what ? Electric charge ?
 
Electric charge is all I can see (thinking back to Griffith's book).
 
Consider the electric field of an idealized electric dipole. It has only closed field lines, but it can do work on a charge.
 
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