Talk:Magnetic flux

Article Does Not define magnetic Flux

This article should be deleted because it is useless as a definition. There is no place where it shows how to calculate the magnetic flux from a definition of it. Of course engineers have been designing electric machines for over 100 years using this concept, so there is a way to do it. Since magnetic flux is the dual concept to quanity measure of electricity or charge, it is important that a procedure be given to calculate magnetic flux. But I can't find it here.

According to history, the above was written by 71.251.190.82. I made the heading. --Treekids (talk) 18:40, 12 June 2008 (UTC)

I agree- the definition is inaccurate and tautologous when corrected. Magnetic field (H) is a completely different concept from flux, and if you replace the erroneous 'field', by the correct 'flux', the defintion becomes 'Flux is the amount of flux'. What kind of defintion is that ? What kind of imbecile has written this crap anyway ? —Preceding unsigned comment added by 82.32.49.157 (talk) 19:31, 28 February 2011 (UTC)

Proof

The given "proof" that the flux through a closed surface being zero seems backward. It starts from a vector potential A with curl A = B and then proves that div B = 0. In reality it is just the opposite. One of Maxwells laws states that div B = 0. As a consequence there is a vector potential A with curl A = B. −Woodstone 21:42, 2005 Apr 9 (UTC)

adds and removed

I added the reference to Maxwell's equations because of that, but it is still unsatisfying. Lemme see how it can be reworded. --Laura Scudder 23:32, 9 Apr 2005 (UTC)

I just removed the reference to the vector potential since it has no direct connection to discussion. --Laura Scudder 23:43, 9 Apr 2005 (UTC)

Equations need revamping

This page needs to have variables explained better. I added some explanation, but others I'm not sure how to expand on. Also, am I right that B (the magnetic flux density) is the same thing as a "magnetic field" ? If so that should be noted, because both terms are common.

No - flux density (B) and field (H) are completely different concepts with different dimensions and units (Tesla and A/m repectively in the SI system). B = Hu where u (mu) is the permeability of a material. u has units of Henry/metre; u0, the permeability of free space is 1.257*10^-6H/m. The problem is that in the USA writers are extremely careless about use of the term 'magnetic field', and habitually confuse it with flux density. God knows how they can do science or engineering with that kind of mind set. Possibly the reason for this is that in that country the cgs system is still in use, and in that system B and H are identical (so I have been told, but I have never used that system of units myself). —Preceding unsigned comment added by 82.32.49.157 (talk) 19:39, 28 February 2011 (UTC)

"Layman"

The article states that:

Magnetic flux density, otherwise known as magnetic field density, is essentially what the layman knows as a magnetic field

It's also what pretty much every physicist knows as the magnetic field, and authors like Jackson and Griffith concur on such usage. So I think "the layman" here is a bit misleading. --Starwed 13:08, 27 February 2007 (UTC)

No - the layman and the scientist or engineer differ here - see my comment immediately above. AJS

Template:Electromagnetism vs Template:Electromagnetism2

I have thought for a while that the electromagnetism template is too long. I feel it gives a better overview of the subject if all of the main topics can be seen together. I created a new template and gave an explanation on the old (i.e. current) template talk page, however I don't think many people are watching that page.

I have modified this article to demonstrate the new template and I would appreciate people's thoughts on it: constructive criticism, arguments for or against the change, suggestions for different layouts, etc.

To see an example of a similar template style, check out Template:Thermodynamic_equations. This example expands the sublist associated with the main topic article currently being viewed, then has a separate template for each main topic once you are viewing articles within that topic. My personal preference (at least for electromagnetism) would be to remain with just one template and expand the main topic sublist for all articles associated with that topic.--DJIndica 16:45, 6 November 2007 (UTC)

+ or -

${\mathcal {E}}=\oint \mathbf {E} \cdot d\mathbf {s} =-{d\Phi _{m} \over dt}.$
Better: + or -
Martin Segers (talk) 08:24, 6 January 2008 (UTC)

gibberish

Figure 3: A vector field F ( r, t ) defined throughout space, and a surface Σ bounded by curve ∂Σ moving with velocity v over which the field is integrated.

Can someone re-word this? --Treekids (talk) 18:38, 12 June 2008 (UTC)