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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)
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)
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)
The article states that:
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 —Preceding unsigned comment added by 82.32.49.157 ( talk) 19:41, 28 February 2011 (UTC)
I want an easier definition because I didn't get that one. ClintJCL ( talk) 02:18, 4 December 2012 (UTC)
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)
Better: + or -
Martin Segers (
talk) 08:24, 6 January 2008 (UTC)
Can someone re-word this? -- Treekids ( talk) 18:38, 12 June 2008 (UTC)
What is the definition of flux through a coil doing there? Its nothing more than applying the general definiton of magnetic flux (in fact the equation is a repeat of the definition - and once again the dot for the dot product is missing). The section is too short anyway, hence its redundant. The section makes it appear that the flux through a coil has a seperate/special case definition.
On the other hand - the video is certainly good to include.
Given these issues - I deleted everything in the section except the video and a sentence related to the video.
If there is any favour to restore the section and extend it to some volume - please do. F = q(E+v×B) ⇄ ∑ici 13:59, 25 March 2012 (UTC)
I also tried to tidy the positioning of the images - if according to your browser the images still are cluttered: tweak as neccersary. F = q(E+v×B) ⇄ ∑ici 14:01, 25 March 2012 (UTC)
==
The text states "(see below for deciding in which direction the field lines carry a positive sign and in which they carry a negative sign).", but there is no further mention of this.
Modelmat ( talk) 08:57, 24 March 2021 (UTC)
The equation for magnetic flux on the page says that Φ = B⋅S = BS sin θ. I don't know what the literature says on the subject, but this equation is mathematically wrong. The dot product of the two vectors B⋅S is BS cos θ. For it to be BS sin θ, you'd need to be talking about the magnitude of the vector B×S or the magnitude of the bivector B∧S. 2603:6080:CC00:193:C9E2:11BE:C088:7008 ( talk) 20:03, 4 August 2023 (UTC)
This is the
talk page for discussing improvements to the
Magnetic flux article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This
level-5 vital article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||
|
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)
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)
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)
The article states that:
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 —Preceding unsigned comment added by 82.32.49.157 ( talk) 19:41, 28 February 2011 (UTC)
I want an easier definition because I didn't get that one. ClintJCL ( talk) 02:18, 4 December 2012 (UTC)
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)
Better: + or -
Martin Segers (
talk) 08:24, 6 January 2008 (UTC)
Can someone re-word this? -- Treekids ( talk) 18:38, 12 June 2008 (UTC)
What is the definition of flux through a coil doing there? Its nothing more than applying the general definiton of magnetic flux (in fact the equation is a repeat of the definition - and once again the dot for the dot product is missing). The section is too short anyway, hence its redundant. The section makes it appear that the flux through a coil has a seperate/special case definition.
On the other hand - the video is certainly good to include.
Given these issues - I deleted everything in the section except the video and a sentence related to the video.
If there is any favour to restore the section and extend it to some volume - please do. F = q(E+v×B) ⇄ ∑ici 13:59, 25 March 2012 (UTC)
I also tried to tidy the positioning of the images - if according to your browser the images still are cluttered: tweak as neccersary. F = q(E+v×B) ⇄ ∑ici 14:01, 25 March 2012 (UTC)
==
The text states "(see below for deciding in which direction the field lines carry a positive sign and in which they carry a negative sign).", but there is no further mention of this.
Modelmat ( talk) 08:57, 24 March 2021 (UTC)
The equation for magnetic flux on the page says that Φ = B⋅S = BS sin θ. I don't know what the literature says on the subject, but this equation is mathematically wrong. The dot product of the two vectors B⋅S is BS cos θ. For it to be BS sin θ, you'd need to be talking about the magnitude of the vector B×S or the magnitude of the bivector B∧S. 2603:6080:CC00:193:C9E2:11BE:C088:7008 ( talk) 20:03, 4 August 2023 (UTC)