Electric fields vs magnetic fields?

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Discussion Overview

The discussion centers around the relationship between electric fields and magnetic fields, particularly in the context of the Lorentz Force Law and the behavior of charged particles in a current-carrying wire. Participants explore the conditions under which electric and magnetic fields coexist or are absent.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the professor's assertion that only a magnetic force is present in a current-carrying wire, citing textbook statements that suggest moving charges create both electric and magnetic fields.
  • Another participant explains that in an uncharged wire, the electric fields from electrons and protons cancel each other out, resulting in a magnetic field without an electric field.
  • A third participant confirms that if the wire is uncharged, there is no net electric field from it.
  • A later reply acknowledges a misunderstanding regarding the balance of protons and electrons in the wire, indicating a need for clarification on the relationship between charge distribution and field presence.

Areas of Agreement / Disagreement

Participants express differing views on the presence of electric fields in relation to magnetic fields in a current-carrying wire. There is no consensus on the interpretation of the relationship between these fields, and the discussion remains unresolved.

Contextual Notes

Participants reference various textbooks and external materials, indicating potential limitations in understanding the definitions and conditions under which electric and magnetic fields interact. The discussion highlights the complexity of charge behavior in conductive materials.

Ascendant78
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Electric fields vs magnetic fields?

Ok, so in class last week, I had asked my professor about using the Lorentz Force Law to solve a particular problem. When he responded with "we only have a magnetic force from the current in the wire, so we don't have to worry about an electric field," that completely threw me for a loop.

A quote directly from our course's textbook, "All moving charged particles create magnetic fields... This is in addition to the electric field that is always present surrounding charged particles." A quote from another textbook, "A moving charge always has both a magnetic and electric field." Based on these statements and other external materials I read regarding the matter, I thought that whenever you have a magnetic field (excluding permanent magnets), you always have an electric field? I know I have read this in at least one or two other places as well, but maybe I'm just missing something here? If someone could clarify, I'd appreciate it.
 
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The wire is uncharged. All of the electric fields of the electrons are canceled out by the electric fields of the protons. However, since the electrons are moving and the protons are not the magnetic field of the electrons is not canceled out. Therefore, you get a magnetic field and no electric field.
 
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Your wire is uncharged, right? Then there is no net electric field from it.
 
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Ok, I wasn't aware the no matter how much current flows through the wire, the proton to electron ratio is still always balanced. That was where my problem was... well that and misunderstanding the statements regarding charges and their fields. Thanks.
 

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