Question about Maxwell's Equations

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    Maxwell's equations
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Discussion Overview

The discussion centers on the possibility of deriving Faraday's Law from the other three Maxwell equations along with the conservation of charge. Participants explore the relationships between these equations and the implications of empirical versus axiomatic derivations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions whether Faraday's Law can be derived from the other Maxwell equations and conservation of charge.
  • Another participant asserts that conservation of charge is unrelated to Faraday's Law, emphasizing that Faraday's Law pertains solely to fields.
  • A different viewpoint suggests that taking the divergence of Maxwell's curl H equation leads to the continuity equation, which relates to conservation of charge, but does not allow for deriving Faraday's Law from the others.
  • Some participants propose a method involving the curl H equation and the divergence to show a connection to Faraday's Law, although this is met with skepticism regarding its validity.
  • One participant argues that Maxwell's Equations are empirical laws and cannot be derived axiomatically, suggesting that experimental evidence is necessary to establish Faraday's Law.
  • There is confusion expressed about the relationship between the derivatives in Faraday's Law and the proposed derivation method, indicating a lack of clarity on the equivalence being claimed.

Areas of Agreement / Disagreement

Participants express differing views on whether Faraday's Law can be derived from the other Maxwell equations and conservation of charge. There is no consensus on the validity of the proposed methods or the relationships between the equations.

Contextual Notes

Some claims rely on specific interpretations of the equations and their relationships, which may depend on definitions and assumptions that are not fully explored in the discussion.

lugita15
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Is it possible to derive Faraday's Law from the other three Maxwell equations plus the conservation of charge? If so, how?

Any help would be greatly appreciated.
Thank You in Advance.
 
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Conservation of charge is not related to Faraday's law in any way, since Faraday's Law has absolutely nothing to do with charge. Faraday's law only talks about fields.

Faraday's Law cannot be derived from the other equations. If it could, it wouldn't be considered one of Maxwell's equations.
 
If you take the divergence of Maxwell's curl H equation, you get the continuity equation, which is equivalent to conservation of charge (if you use the div D equation). But you can't go the other way, although that is probably how Max deduced the D dot term.
 
You can go the other way, to some extent.
1. Start with the curl H equation with only the j term on the right.
2. Take the divergence of both sides.
3. This gives div j=0, but div j =-d rho/dt.
4. This requires adding the d D/dt term (using the div D Maxwell eq.) , which is equivalent to Farady's law.
 
Meir Achuz said:
You can go the other way, to some extent.
1. Start with the curl H equation with only the j term on the right.
2. Take the divergence of both sides.
3. This gives div j=0, but div j =-d rho/dt.
4. This requires adding the d D/dt term (using the div D Maxwell eq.) , which is equivalent to Farady's law.

How is that equivalent to Faraday's law? Faraday's law relates d B/dt to curl E, not d E/dt to curl B. Doesn't it? :confused:
 
My understanding is this: despite their mathematically rigorous statements, Maxwell's Equations are all empirical laws, meaning that they can't be derived by any axiomatic approach. As such, the only way to "derive" Faraday's Law would be to do a physical experiment and deduce it. In this case, you'd need to alter the magnetic flux of a conducting loop, and show that the line integral of the electric field (=the EMF) is equal to the rate of change of flux through the loop. But since each of Maxwell's equations say different things about the electric and magnetic fields, I can't think of a way in which you could derive any of them from the others.
 
Xezlec said:
How is that equivalent to Faraday's law? Faraday's law relates d B/dt to curl E, not d E/dt to curl B. Doesn't it? :confused:
Yes, I just got careless.
 

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