Why maxwell's 3rd equations has no coefficient?

  • Context: Graduate 
  • Thread starter Thread starter lowerlowerhk
  • Start date Start date
  • Tags Tags
    Coefficient
Click For Summary

Discussion Overview

The discussion centers on the nature of coefficients in Maxwell's equations, specifically why Faraday's Law (the third equation) has a coefficient of -1, while the other equations include dimensional constants. Participants explore the implications of unit choices on these coefficients.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that only Faraday's Law has a coefficient of -1, questioning why it is not a materially dependent coefficient k.
  • Another participant suggests that the coefficient's nature depends on the units used, specifically mentioning Gaussian units where electric and magnetic fields are measured in the same units.
  • Some participants agree that the choice of units is crucial, emphasizing that this leads to the absence of a coefficient in Faraday's Law.
  • Several participants raise the question of why the other three equations include dimensional constants, attributing this to the use of different units for electric and magnetic fields, despite their relationship as parts of the same tensor.
  • One participant emphasizes the historical context of unit choices, likening it to measuring distances and times in different units.

Areas of Agreement / Disagreement

Participants generally agree that the choice of units affects the coefficients in Maxwell's equations, but the discussion remains unresolved regarding the implications of these choices and the historical context behind them.

Contextual Notes

The discussion highlights limitations related to the dependence on unit systems and the historical context of measurement, but does not resolve the implications of these factors.

lowerlowerhk
Messages
27
Reaction score
0
For the four Maxwell equations, only the third one (Faraday's Law) has a proportionality coefficient of -1, while rest have a magnetic constant or electric constant .

It doesn't seem like the units of the third law are calibrated to eliminate the constant. So why is the coefficient equal to exactly -1, not some materially dependent coefficient k?
 
Physics news on Phys.org
  • Like
Likes   Reactions: Dale
I second jasonRFs comment. It is purely due to the units chosen.
 
The real question is, why do the other 3 equations have dimensional constants introduced. That is because they use different units for E and B, even though they are parts of the same tensor.
 
Meir Achuz said:
The real question is, why do the other 3 equations have dimensional constants introduced. That is because they use different units for E and B, even though they are parts of the same tensor.

But this is historical - like measuring distances and times in different units. Time should be measured in meters.
 
Meir Achuz said:
The real question is, why do the other 3 equations have dimensional constants introduced. That is because they use different units for E and B, even though they are parts of the same tensor.

This is the answer I am looking for.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K