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I think it would be very useful to have a small list of the Efields of charged surfaces, like spheres, cylinders, wires, etc. Fresheneesz 19:13, 10 May 2006 (UTC)
The first line read that an E field excerts a force on "objects" i put in "electrically charged" infront of objects, since this is more correct. An object wont feel a force from an E field unless it is charged itself. -- Robertirwin22 20:11, 13 May 2007 (UTC)
I don't like the formulation with the r vector on top and the r^3 on the bottom. Can we have r^2 on the bottom and an r unit vector on top? I think for young people (high school students) this could be confusing to them. It might lead them to think that the electrostatic force is proportional to 1/r^3, which it is not. For the article to be written for all audiences, I believe it should use the form that I prefer, using a unit vector instead. Comments? -- Dave
I'm basically boycotting TeX -- I didn't participate in "texification" except in a few special cases. See wikitech-l Jan 2003 under "ugly <math>" for why -- I argued that it's ugly, due to being too large compared to the text, but everyone just ignored me and argued against me on all sorts of silly little points while ignoring the obvious issues. Also, you can't wikify TeX like you can HTML -- if it was up to me I would have left the magnetic field formulas like this. Getting back the point, no I don't think there is any consensus, although I wasn't really following the mailing lists back then. Now that the range of TeX displayed as HTML is bigger than it was originally, you can probably use TeX in most cases. -- Tim Starling 06:50 Apr 1, 2003 (UTC)
Ghitis -- your new definition did not use standard physics language, so I reverted it. The electric field is a very well-defined concept in physics, and 'spatial manifestation' and 'material entity' are not. Tantalate 19:57, 26 Aug 2004 (UTC)
I think that both forms are important and that unless there is a good reason not to, the equations should look more like : Most, if not all advanced E&M textbooks include both, and with good reason: there are times when each is advantageous over the other. -- Scott
In my opinion, the most definite and illustrative formulas for the electric field are for the set of point charges and for the continuous charge distribution. These forms emphasize the fact that the field is determined at the point and is caused by either charged particles at points or the charge density in all points in the volume . These formulas were used in the book on electromagnetism by Grant and Philips. What do you think? Do they look too complicated? -- Jmattas 09:58, 8 August 2007 (UTC)
Someone created the page Uniform electric field. I don't think we need a page like that. What do you think? Should it be deleted? Merged with this page? Or expanded into a full article? (What would it talk about?) -- Coppertwig 21:29, 20 September 2007 (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 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 16:31, 6 November 2007 (UTC)
The derivation takes up too much space, and shouln't be at the top. Not only that, most of that derivation is describing coulomb's law which should simply be linked to. I'll do that if noone objects. Fresheneesz 06:46, 3 May 2006 (UTC)
The permittivity of a vacuum is not 'usually 7'. I'm removing that from the Coulomb's Law section. -MrDeodorant, December 15 2007 —Preceding unsigned comment added by MrDeodorant ( talk • contribs) 04:42, 15 December 2007 (UTC)
I added the SI base units to the introduction because I feel it would improve the article. Any objections? Bdforbes ( talk) 21:26, 21 November 2008 (UTC)
The article gives the unit for electric fields as Zoids. I can find no reference to this as a unit of measure equal to N/C. —Preceding unsigned comment added by Omicron84 ( talk • contribs) 02:10, 17 May 2009 (UTC)
It was posted by "Zoidfather", the "Zoid" is not a unit of measurement and appears to have been spam. I've removed it. Hungryhungarian ( talk) 17:32, 21 May 2009 (UTC)
It is very misleading to begin this article with a definition in terms of potentials. Historically, the electric field was seen as an abstraction of the electric force, and the most intuitive definition was through the formula F = q E for static fields. Topics such as elementary particles and vector potentials should be left our or included only parenthetically. 146.6.178.202 ( talk) 17:24, 8 September 2009 (UTC)
I'm not an expert on dimensions. But I think the kg·m·s−4·A−1 unit needs to be revised. Nedim Ardoğa ( talk) 08:10, 13 July 2009 (UTC)
Whatever the dimensions of electric field may be, the SI UNIT is volts/metre. Please correct this .. Andrew Smith —Preceding unsigned comment added by 82.32.50.77 ( talk) 10:23, 3 January 2010 (UTC)
The previous version of the Definition section seemed to be focused on defining electric charges rather than the electric field. I edited that information out and also merged the Coulomb's Law section, since it was essentially defined in terms of Coulomb's Law (and Gauss's Law). I included several common equations that could be used as mathematical definitions of electric field. It might still need a little more cleaning up right at the end, however, but it should be accurate, at least. 71.225.188.211 ( talk) 23:39, 10 February 2010 (UTC) To me it is most obvoius that uncontrolled democracy is undistinguishible from pure chaos. Just listen to this mambo-jambo "In physics, an electric field is a property that describes the space ". Describes what? The space? And further down where the charge q approcahes zero. I am professional engineer and through my entire career I have know that the the probe charge is REMOVED to infinity. And the same with the rest of the .....Lord almighty, where are we going! —Preceding unsigned comment added by Sergei.Borodinski ( talk • contribs) 19:15, 12 February 2010 (UTC)
By Heldervelez: The 'fathers' of electrodynamics believed in an infinite universe in time, but we know now differently. The integration extended to ALL space is incorrect. One can only integrate inside the light-cone, and the E-field energy becames a time growing value, instead of a constant one. To preserve the energy of the entity particle+field the mass of particle must decrease thru time. The killing error is presented here: and discussed at BautForum ATM Links to a new model of the universe based on 'Evanescence' is also presented there. I'm willing to make a reference to this claim as Controversy. Any ideas ? —Preceding unsigned comment added by Heldervelez ( talk • contribs) 18:35, 24 September 2010 (UTC)
For well over 100 years now scientists have been raised to believe that real world stuff can be defined to BE a mathematical models. Example from this article: "The electric field !!! IS !!! a vector field". Wether or not this phenomena IS photons or IS something else from the real world is irrelevant (I personally believe it's a property of spacetime just as curvature is). It is, as the above writer states, "as real as kangaroos" and definitely not a "vector field" which is a mathematical invention nowhere to be seen in the real world. This definition and (many others) need to be changed to something like "a phenomena that can be mathematically represented as" a vector field. —Preceding unsigned comment added by 109.186.43.95 ( talk) 18:22, 13 November 2010 (UTC)
This is unnecessarily verbose - 'The strength or magnitude of the field at a given point is defined as the force that would be exerted on a positive test charge of 1 coulomb placed at that point; the direction of the field is given by the direction of that force.' Since E has been defined as a vector, and force is also a vector, it suffices to say 'E is defined as the force, of electric origin, on a unit positive charge'. Simplicity makes for clarity, I feel. —Preceding unsigned comment added by 82.32.49.157 ( talk) 08:37, 25 November 2010 (UTC)
Main changes:
For those that wrote the article and who I may be insulting: don't get me wrong - its good to add external links and try etc, but better to use secondary sources more than primary. =)
-- F = q( E + v × B) 01:16, 28 February 2012 (UTC)
I reverted these [1] changes as they appear to move away from standard notation. IRWolfie- ( talk) 13:16, 9 July 2012 (UTC)
Definition Problem: The current definition on the page is: "The electric field E is defined as the force F experienced by a stationary positive unit point charge q at position r (relative to Q) in the field". Problem: The Electric field is not a force. It is not even a set of forces. It is a set of forces per unit charge that can be defined by a vector-valued function. The most important change that needs to be made is the part about force per unit charge. By analogy, one can reference gravitational field. One would never say that "The gravitational field G is defined as the force F experienced by a stationary point mass m at position r (relative to M) in the field". The reason is that the gravitational field is not a force. Mathematically, it is a tool for computing any force affected by the field. Here is my suggestion for changing the definition (I use rectilinear coordinates because they are familiar to more readers):
Consider a point charge q with position (x,y,z). Now suppose the charge is subject to a force due to other charges. Since this force varies with the position of the charge and by Coloumb's Law it is defined at all points in space, is a continuous function of the charge's position (x,y,z). This suggests that there is some property of the space that causes the force which is exerted on the charge q. This property is called the electric field and it is defined by
Notice that the magnitude of the electric field has units of Force/Charge. Mathematically, the E field can be thought of as a function that associates a vector with every point in space. Each such vector's magnitude is proportional to how much force a charge at that point would "feel" if it were present and this force would have the same direction as the electric field vector at that point. It is also important to note that the electric field defined above is caused by a configuration of other electric charges. This means that the charge q in the equation above is not the charge that is creating the electric field, but rather, being acted upon by it. This definition does not give a means of computing the electric field caused by a group of charges.
Being somewhat unfamiliar with HTML or whatever, I could not get the subscripts to have a space; It should say "On q", not "On'q". Someone who knows what they are doing should maybe help out with that if they get a second.
Qualitative Description Problem: The qualitative definition makes the same mistake of defining the E field as a force that would hypothetically exist under some condition, rather than force per unit charge, but I am willing to give some artistic license to the qualitative description. My problem is with the last analogy: "...The electric field is to charge as gravitational acceleration is to mass and force density is to volume." I like the gravity analogy, but I have no idea what this is referencing: "force density is to volume". That might be true in some context, but I have a degree in physics and nothing springs immediately to mind. I recommend clarifying the context or just scrapping it because it is confusing. It might even be misleading because definitions of E field often reference space which is not meant in the every-day sense of the word; In mathematics, space is a set of points which is very different than a scalar associated with some set of points (which is what volume is).
I will wait a little and see what people think of this and if I do not get any complaints I am going to change the definition in the article. I have not read the citations in the article, but I have read a couple of other resources (college text books) that I can cite in the article that back up my definition. I suspect that the other sources give accurate definitions, but that they were misinterpreted when paraphrased. — Preceding unsigned comment added by SortOfStillCare ( talk • contribs) 14:26, 26 July 2012 (UTC)
I notice that Special:Contributions/83.131.29.96 has changed magnetic flux density to magnetic field in a number of articles. I am conscious that a blanket reversion could antagonize, but magnetic flux density would seem to be correct in this case. It would facilitate discussion if this user acquired a name. Incidentally, I would agree that the distinction between flux and field could disappear in more advanced treatments using some system of natural units (and in the historical emu system? (I forget)). However, the fact that this article is called Electric field, and not say electromagnetic tensor, suggests a more elementary approach is appropriate. -- catslash 17:56, 7 July 2007 (UTC) hhkjhhgjhighgjih — Preceding unsigned comment added by 12.218.113.146 ( talk) 18:01, 12 October 2012 (UTC)
I've been looking at the section on electrostatic fields, and it is quite messy. Equations seem to be presented out of order (or at least the descriptions of them are out of order). Also, there is an equation derived from Coulomb's Law that is simply in the text and not explained in any way. I don't know where to start to rewrite this section, but it definitely needs some work. K of slinky ( talk) 14:28, 10 July 2012 (UTC)
what is the electric field
electric field is area of charge, whare another charge partical expirinced the force of atreaction or repeltion. — Preceding unsigned comment added by 101.215.149.52 ( talk) 03:20, 15 October 2012 (UTC)
I noticed repeated use of the capital letter theta for electric potential. Besides the fact that I've only seen potential represented by V, I found that the Wikipedia article on potential does not use this notation either. I believe this notation may confuse people who usually see electric flux represented by theta. Does anyone know why this letter may have been used here in this context? ~Username222 ( talk) 01:05, 29 January 2013 (UTC)
The first two sentences here read:
An electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the surrounding force of an electrically charged particle exerted on other electrically charged objects.
I'm curious, what language is that? It has some superficial resemblance to English, but lacks the crucial characteristic of communicating meaning to others who speak the same language. Would someone with some fundamental understanding of the basics of the topic perhaps like to write a couple of sentences that lay out clearly what an electric field is? I believe that would make a good opening to an article on the subject. Just to be clear, we don't need to know what it surrounds (how does it know where the limits of the "time-varying magnetic fields" lie, by the way?), or what it depicts; but it'd be really handy to know what it actually is. Thanks, Justlettersandnumbers ( talk) 00:31, 16 July 2013 (UTC)
can we add that electric field is a model in physics that represent the medium in which charged particles can apply force to each other? because even though electric fields represent natural behavior extremely well the electric field itself does not exist, it an mathematical model. kfir 09:15, 10 September 2013 (UTC) — Preceding unsigned comment added by Comixdude ( talk • contribs)
The electric field is a vector field. The field vector at a given point is defined as the force vector per unit charge that would be exerted on a stationary test charge at that point. An electric field is generated by electric charge, as well as by a time-varying magnetic field. Electric fields contain electrical energy with energy density proportional to the square of the field amplitude. The electric field is to charge as gravitational acceleration is to mass. The SI units of the field are newtons per coulomb (N⋅C−1) or, equivalently, volts per metre (V⋅m−1), which in terms of SI base units are kg⋅m⋅s−3⋅A−1 — Preceding unsigned comment added by 122.144.124.104 ( talk) 03:15, 12 December 2013 (UTC)
In the definition (and in the entire article), A is not defined and I do not understand what it stands for. I think this should be explained. -- Arnaud Dessein ( talk) 12:42, 16 March 2009 (UTC)
It's an SI representation of Ampere SI:
Current (1946): The constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2×10−7 newtons per metre of length. Mwasheim ( talk) 19:48, 9 April 2014 (UTC)
There exists an article called electromagnetic field. And yet another called electromagnetism that describes the EM interaction (the EM fundamental force).
So what are these articles about the electric field and the magnetic field? They are just articles about the electromagnetic field when seen by a privileged observer-- one who misses one field component because he's positioned just right in space and time.
That's like looking at a cube from JUST the right angle to see a square, where any other place when show you a 3-D object. There isn't any PLACE that "has" an electric or magnetic field. Because any observer at such a place simply needs a velocity and will no longer see a pure E or B, but a mix. So it's both a place AND an inertial frame that seems to have just one field. So even though you can imagine an E field in a given place and frame, if you move, it's all screwed up and now you have both E and B.
There is an analogy with kinetic energy: if you hold position with regard to an electron, you will just its E field. And you ALSO will see no kinetic energy of the electron. But if it moves, or if it stays the same place but YOU move, you will no longer see just an E field, but now you see a new B field, and (moveover) also see that your electron "has" kinetic energy.
So is a "pure" E field "real"? Is it even worth the long discussion here? If the E field from a distant particle is no more real than the kinetic energy of that distant particle (which comes and goes, depending on how you look at it, and what frame you look at it), then how real is that? S B H arris 05:42, 31 July 2013 (UTC)
E-fields are just mathematical abstractions? No. Since the time of Maxwell we have known that e-fields and b-fields are two facets of electromagnetic fields and they contain electrical energy. E. g., if a positive charge is pulled away from a negative charge, energy is stored in the surrounding e-field pattern. (A mathematical abstraction cannot store electrical energy!) In modern QM and Gauge theory, we regard the classical fields as being caused by photon exchange, both magnetic fields and electrostatic fields are "made" of photons.-- Wjbeaty 11:22, Feb 28, 2005 (UTC)
I like Wjbeaty's example. I've come to realize that gravity cannot create energy but it can store energy. From this I'm trying to learn about radiation energy and momentum energy. In my study, radiation got me to electromagnetic radiation, which got me to electric field, which got me here. But, except for the one example by Wjbeaty, not much seems easy to understand. I think things should be explained using the least amount of complicated terms as possible. Not pointing fingers, but people often try to showoff their knowledge by using complicated terms that just make it impossible to understand an idea. Of course the complex formulas are great and needed for practical purposes. But before I get to those I need to understand what an electric field is, how it is created, what it affects, etc. I did learn that an electric field is always accompanied by a magnetic field but how it relates I'm still not sure. Of course, perhaps I just didn't try hard enough to understand so this is just an opinion that may or may not help improve this page in the future. Darcy MacIsaac 63.135.12.196 ( talk) 20:14, 9 July 2014 (UTC)
Is this ever called E-field? I would like to replace "In physics, an electric field or E-field" with "In physics, an electric field (also known as an electrostatic field)" since 'electrostatic field' is very common usage (I just saw it in the wikipedia requests and redirected to this page) Shameer 03:12, 14 Feb 2005 (UTC)
In physics, we always called 'em by the names "e-field" and "b-field." The phrase "electrostatic field" has too many syllables for convenient use in heated late-night conversations! Search google for e-field: 149,000 hits, while "electrostatic field" gets only 75,000 hits: [2]
In the definition section there is the phrase:
This definition does not give a means of computing the electric field caused by a group of charges.
I don't think this is true since the assumption of point charge was never made. I suggest to remove that line.
AsafPM ( talk) 19:12, 6 November 2014 (UTC)
Hello to all,
I have been WP:BOLD and edited the article heavily ( diff of my changes).
I removed a lot of things on my way, hopefully it contains less gibberish now, but valuable content that I did not recognize as such might have been lost. There is still a huge need for inline citations. Picture would be valuable.
If you do not feel like editing but still would like to mention something that is not right, please do.
I will change the issue template at the top of the page to reflect what I expect to have done, but feel free to put it back in place if you think it still belongs there. Obviously, I am not the best judge of my own edit-orgy.
Tigraan ( talk) 15:13, 24 December 2014 (UTC)
The current into paragraph is:
"The electric field is a component of the electromagnetic field. It is a vector field and is generated by moving electric charges or time-varying magnetic fields, as described by Maxwell's equations.[1] The concept of an electric field was introduced by Michael Faraday.[2]"
Which I believe can be better understood if reworded as follows:
The electromagnetic field is a spatial vector field which is generated by moving electric charges or by time-varying magnetic fields, as described by Maxwell's equations.[1] The electric field,(this article) which is one component of the spatial vector field, is perpendicular to the other component of the spatial vector field, which is the magnetic field. The concept of an electric field was introduced by Michael Faraday.[2] — Preceding unsigned comment added by DPHutchins ( talk • contribs) 08:03, 29 February 2016 (UTC)
I'm pretty new here, but I'm trying to help make the electromagnetics articles less messy and more readable. I notice there is a separate article (a stub) for electric field intensity. It should be removed, and instead pointed here, right? I'm adding mention of that term to this page, in addition to some other readability changes. Please let me know if I do anything bad! Xezlec
I disagree with the use of the term "electric field intensity" in referring to the electric field vector. Traditionally the term intensity refers to the modulus squared of the electric field (or the square of the electric field strength to use the terminology in the article). Intensity is a scalar quantity, not a vector. Regards, Justin Hannigan.
same. Regards Sevil Natas — Preceding unsigned comment added by 58.106.66.223 ( talk) 10:54, 10 October 2017 (UTC)
Hi Jennica. I can't figure out my "Talk" system. So not sure if this will reach you. Have you noticed what I've been doing? I haven't since October 28 changed anything in the body of the subject discussion. I have added references (as you guys have asked for) from one of the most popular and long time university texts on the subject of Electricity and Magnetism: Edward Purcell PhD, University of Cambridge, 820 pages. Also from professor Browne's book. These are very appropriate footnotes to the various subject paragraphs and reinforce those subjects plus I have quoted what they wrote. There could be more over time. But block me if you wish. John DeVore e-mail: jw@jwdevore.com — Preceding unsigned comment added by 73.81.156.127 ( talk) 17:40, 31 October 2017
HEY EDITOR: In the past two days I have tried to add very applicable reference sources to four similar and related wikipedia electromagnetic articles, the bulk of which at even with the first introduction paragraph are baffling to anyone but a graduate scientist. Definitely I'm not attempting to vandalize. Rather than lead off "ELECTRIC FIELD" with Feynman's accurate but novice baffling discussion of an electric field using terms like Coulomb and infitestimal particle not already defined or explained, how about leading off with two or three sentences that provide the novice an image in his mind of wat is to come? How many non-science types know what a "charge" is? Some, sure, but EVERYONE has a mind picture of an electron whirling around in his high school science class molecule video. So, start with an electron in the first paragraph, call it a charge from here on, and discuss the fact that this electron "charge" has a field surrounding it which it creates. And that affects everything around it. By a FORCE. Or as reference professor Browne (page 225) says, a charge has an "aura" around it. Then the paragraphs following can get more complex (after all, it IS a complex subject) and can bring in a sea of integrals and other equations which stop most people cold in which they then stop reading and go on and look something else up. I'm a retired electrical engineer who had a few college courses in electrodynamics and radio transmission theory and was very lucky to get Cs in those curve busters and am trying NOW to get a better grip on the subject. Oh, and just try to figure out the REFERENCE and NOTES and OTHER READING system of WIKIEDIA. Its as confusing as Gauss. John DeVore, Doylestown, PA, jw@jwdevore.com — Preceding unsigned comment added by 73.81.156.127 ( talk) 20:46, 28 October 2017
Please explain better the distinctions between the terms electric field, electric field intensity (magnitude of the electric field vector) (E) ( V/ m), electric field strength (vector quantity), electric field gradient, E-field, and so on. What are the units of each? - Omegatron 13:16, July 19, 2005 (UTC) I'm pretty new here, but I'm trying to help make the electromagnetics articles less messy and more readable. I notice there is a separate article (a stub) for electric field intensity. It should be removed, and instead pointed here, right? I'm adding mention of that term to this page, in addition to some other readability changes. Please let me know if I do anything bad! Xezlec
Okay, I went ahead and did the above-mentioned redirect. This is ok, right? Xezlec 04:11, 31 December 2005 (UTC)
Sorry for continued nitpickery. I've now expanded the article to mention that a changing B-field also produces an E-field. I revised some things to make it clear that most of the rest of the article applies only to the static case. I'm not sure the overall structure of the article is still "pretty-looking" but at least it's more complete and more strictly correct now. Xezlec 06:45, 31 December 2005 (UTC)
I disagree with the use of the term "electric field intensity" in referring to the electric field vector. Traditionally the term intensity refers to the modulus squared of the electric field (or the square of the electric field strength to use the terminology in the article). Intensity is a scalar quantity, not a vector. Regards, Justin Hannigan.
Smythe's "Static and Dynamic Electricity" refers to E (the vector) as "electric field intensity". Also see Marion + Heald, p3, which calls it "electric intensity vector or electric field vector". Pfalstad 19:18, 26 September 2006 (UTC)
I agree with Justin Hannigan. The standard terminology is simply electric field.--24.52.254.62 06:21, 3 November 2006 (UTC)
The term "E-field" currently occurs in the lead sentence of two sections of the article, but is nowhere defined. The reader is left guessing whether it means "electric field", as might be inferred by the frequent use of that term in the preceding sections. The term "E-field" should either be defined early in the article, or replaced by a term that has been defined. — Wdfarmer ( talk) 20:27, 25 September 2018 (UTC)
An anonymous editor added some text [3] including the words:
This gives the impression that the article is arguing with itself. Can anyone think of a better way of putting it? The wording of that whole edit could be clearer. Thanks. -- Heron 22:36, 2 July 2005 (UTC)
Field intensity is not mentioned in the article. Does that mean they are the same? — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 16:52, 28 February 2020 (UTC)
The electric field is a vector field. That is to say, every point in 3-dimensional space has a vector attached to it that contains the direction and magnitude of the electric field at that point in space. So you can say that E = {E_x, E_y, E_z}. The direction of the electric field is contained in this vector due to the relative magnitudes of E_x, E_y, and E_z. The magnitude of the electric field is found by using the Pythagorean theorem in 3D, or |E| = sqrt(E_x**2 + E_y**2 + E_z**2). Also, in pictorial representations of the electric field, the density of the lines will generally correspond to the intensity of the field. Footlessmouse ( talk) 22:42, 12 August 2020 (UTC)
Although MUCH better in its introduction and general organization than than the Wikipedia article "Magnetic Field," this Wikipedia article Electric Field can only be understood (and that only maybe) by someone who already has a PhD in physics. It is worthless to the uninitiated, yet the uninitiated are those who you want to use Wikipedia as an encyclopedic information source. — Preceding unsigned comment added by 108.36.71.119 ( talk) 23:05, 19 March 2020 (UTC)
My sugestion would be tat teintroductoryparagrap be much briefer. Maybe just a few sentences. Then the next heading be "What is a force field" A few sentences to explain this. Then the next "What is a charge." Then "What is a magnetic field (and also an Electric Field) even though yoone can't see it." That is the probem to the uninitiated: this subject can't be seen, can't be felt unless one has iron fillings in their mouth (ha!) , but it must be conceptualized if to be understood well while being taught. Equations provide no mind conceptualization ecept to the math major or the physics major I realize tyat I am not making a whole lot of sense here. Mabye an opening paragraph should be "Magnetic Fields for Dummies." J Devore, Doylestown PA. retired antenna designer still trying to fully grasp the subject! (I once told a colleague that a flashlight was an electromagnetic radiation antenna device and got an argument that tapered off as he thought more about it. Yeah, we can SEE the stuff in one part of the EM spectrum. Thus extrapolate what we see into the spectrum we can't see where we are trying to pat down those projections in the antenna's radiation pattern to get all of the power forward for efficiency and also for reducing to the side detection by opposition forces.) — Preceding unsigned comment added by 73.81.156.48 ( talk) 14:05, 21 March 2020 (UTC)
I think we could do a better job of linking to other pages that have the space to explain core concepts better than we can here. If we need to add a section that avoids vectors, I could write a section for a one-dimensional electric field, though it would not add any substance to the article. I do not believe we can dumb down the definition section very much, in fact it should be generalized as it is very static-oriented. Also, a vector field (or force field in general) cannot be defined without reference to vectors and vector calculus. I think it is easier to teach people about the electric field by starting with the potentials and simply taking the gradient and curl of the scalar and vector potentials (and most people know what voltage is, and its a short explanation to teach them potential difference is the difference between the electric potential at two points in space). All of these would link to other pages so as to make this article more concise. We could reword the introduction to include the term force field, which can link to the article and we can defer explanation of what a force field is to that page. The gravitational field article opens as "In physics, a gravitational field is a model used to explain the influence that a massive body extends into the space around itself, producing a force on another massive body." Which I think is pretty good, we could start with a morph of this, like "In physics, an electric field is a force field used to model the influence that one electric charge extends into the space around itself, producing a force on other charges." And go from there, but the wording is still very tricky and that only includes static electric fields. I think one of the key points is that the electric field is a model that physicists and engineers use to quantify the dynamics of charged particles in the presence of a charge or current distribution, it is very mathy and, as a model, has very little applicability to everyday-life. Electronics and electricity and static electricity and many other articles can be linked to for more nontechnical information on the subject. Footlessmouse ( talk) 23:05, 12 August 2020 (UTC)
It would be easier for people to understand if we used a couple of sentences to describe the equations, but it is usually unsatisfying. For instance, I can replace the first sentence of the definition section with
But that is convoluted and it is hard to fit all the details in there and is a pretty bad run-on sentence. Regardless, when the equations make sense, then everything else (mostly) makes sense, so some effort should maybe be spent in making the equations less daunting (across the EM articles). Footlessmouse ( talk) 11:48, 13 August 2020 (UTC)
I object to User:85.2.30.77's recent removal of the picture of a cat with styrofoam peanuts stuck to its fur. This article is very abstract and desperately needs examples of the effects of an electric field in everyday setting for nontechnical readers, and this picture was the only one. Your explanation was the picture was "inappropriate for the context". In what way? As explained in the caption, the styrofoam is held on by the electrostatic field of the charged fur. -- Chetvorno TALK 20:05, 3 August 2020 (UTC)
The cat picture and caption failed to add anything to the article and existed only to confuse readers as to the nature of electric fields. I could just have easily taken a picture of a battery, lamp, computer, cell phone, television, remote control, or anything else electronic and stated that it is proof of an electric field. The statement is incoherent as it requires a great deal of work to see how these phenomena are, in fact, related to the electric field. The same picture and caption are available to view in the static electricity, where it is much more appropriate, as it is an example of static electricity in real life (though, for the record, I strongly object to all frivolous pictures of everyday life examples of electricity in these articles, that is how youtubers and tv shows explain science to children, Wikipedia is an encyclopedia and encyclopedias do not include frivolous examples of phenomena and they certainly do not offer them as "proof" of anything). The figures currently in the article that depict lines of electric flux are the only pictorial representation of the electric field that are relevant to the article. While it may be a great illustration of static electricity, this illustration makes it harder to explain the ideals that underlie the electric field as a whole, as it is a very, very special case of a very general phenomenon. I also do not believe we need to include examples of the effects of the electric field in everyday settings. That is a job for the electronics and electricity (and static electricity) articles. Maybe we can link to them? The electric field is, manifestly, a mathematical means of calculating the effects of distributions of charge, it is not useful for laypersons and has no applicability to everyday-life. I think we should do a better job of pointing to the other articles related to electricity and electric charges so nontechnical readers can follow those links to find more relevant information. Footlessmouse ( talk) 22:20, 12 August 2020 (UTC)
Can we get a 3rd opinion? I will leave the new picture of the girl there for now. Lacking a discussion on the merits of these pictures, by anyone but us, we may have to use arbitration to determine whether they are appropriate. — Preceding unsigned comment added by Footlessmouse ( talk • contribs) 20:46, 13 August 2020 (UTC)
I disagree with Footlessmouse's position here. This is a physics article. If you reach the point where you are asserting that the concept under discussion is purely a "mathematical model" that cannot even in principle be illustrated with a physical example, you've left the bounds of physics altogether. Ultimately models in physics must connect to the physical world, and it's useful to illustrate that connection.
I do prefer the image of the girl to the one with the cat. It more directly illustrates the effect of the electric field: a force exerted on charges by other nearby charges.-- Srleffler ( talk) 23:40, 13 August 2020 (UTC)
Thank you all for your input. It seems as if everyone is either neutral or wants to keep the pictures and it doesn't seem to explicitly break any policies and so withdraw my objection to the new photograph. Footlessmouse ( talk) 04:41, 14 August 2020 (UTC)
To address complaints about the technical nature of the article and also as a partial compromise with @Chetvorno over the cat and girl pictures (see above) I propose we create a new History section that goes above the definition. It will link to a main article History of electromagnetic theory. This will bring it more in line with pages such as the magnetic field and will give nontechnical readers a chance to learn why we use the electric field, from a historical perspective. Then the math that follows is just a generalization of that. This section can include some pictures of the effects of the electric field, as they were discovered historically. I could write a draft of the new history section in the next few days if anyone likes the idea. I, otherwise, object that it is overly technical and overly written and requires a PhD to understand. Many physicist will object to the way many parts of the article is written, as it is simplified at every stage. In the definition section, it is only valid for the extremely unrealistic case of an equilibrium charge distributions in a vacuum, so that all the charges feel a force due to all the other charges, but none of them, save an imaginary test charge, ever move. That is to say, it could, and maybe should, be more technical, not less. We just have to find a way to explain it better. I think a history section may help. Footlessmouse ( talk) 01:02, 14 August 2020 (UTC)
Hi all, reading through other articles, I found electricity#Electric field. It seems to me that the introduction on that page is far superior to the lead of this article and could be used to clean this article up considerably. The introduction there is aimed at nontechnical readers, is well-written, and is easy to understand. It does a good job summarizing the electrostatic content in this article. It also includes some history in it. I believe this, and the proposed history section, is the place to start for trying to make this article more nontechnical friendly. Footlessmouse ( talk) 23:51, 17 August 2020 (UTC)
I have come up with the following as the first sentance of a history section
I find trying to write a history section quite difficult, as it should be short but representative. I am not a historian of science and I find it difficult to pick and choose whose contributions are most important and wothy of mention. (outside the lucky few who get their names attached to equations we still use - i.e. Coulomb, Maxwell, and Faraday). I will think about it more. Neither Griffith nor Jackson provide a satisfactory summary on the history (not that they should have), but I adapted that bit from Jackson's intro. Footlessmouse ( talk) 10:19, 20 August 2020 (UTC)
References
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@ DVdm: I see your justification for rolling back the anonymous user's edit, but I am 99% sure they were right. I am at a loss for finding it in a textbook at the moment, but wanted to send a message to let others know in case they happen to know where to look and can find a source more easily. Footlessmouse ( talk) 09:59, 11 October 2020 (UTC)
Okay!!! I feel dumb for not checking here as one of my first stops, but Landau Lifshitz Electrodynamics of Continuous Media (1963) §68 the propagation of waves in an inhomogeneous medium. "In Maxwell's equations… ε is a function of the co-ordinates." p. 285. Like virtually all physics texts, the book continues to leave it as implicit in the equations:
But this is a reliable source that allows us to at least fix up the text around it. Maybe just drop the explicit functional dependence on position from the whole expression and explain it in text. @ DVdm: Any thoughts? Footlessmouse ( talk) 19:25, 11 October 2020 (UTC)
I'm late to this party, but I think writing is highly misleading. The field is always going to vary according to the geometry of the system. Permittivity is nominally constant, varying with position only when the medium is explicitly inhomogeneous. In some materials it will also vary with field and direction (non-isotropic material). Conceivably, it can vary with time, for instance in a liquid medium where the concentration of a solute is changing, or in a solid that is deteriorating. So would you want to write for completeness? I don't think so; doing so detracts from the essence of the relationship. There's a reason you are struggling to find a textbook that states things this way. Spinning Spark 11:58, 18 October 2020 (UTC)
I think it would be worthwhile for editors knowledgeable in this area to start a section on the commercial, scientific and any other applications of electric fields. -- 147.10.208.4 ( talk) 06:36, 31 January 2021 (UTC)
"the electric field E is referred to as the optical field" fgnievinski ( talk) 03:03, 13 May 2022 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 |
I think it would be very useful to have a small list of the Efields of charged surfaces, like spheres, cylinders, wires, etc. Fresheneesz 19:13, 10 May 2006 (UTC)
The first line read that an E field excerts a force on "objects" i put in "electrically charged" infront of objects, since this is more correct. An object wont feel a force from an E field unless it is charged itself. -- Robertirwin22 20:11, 13 May 2007 (UTC)
I don't like the formulation with the r vector on top and the r^3 on the bottom. Can we have r^2 on the bottom and an r unit vector on top? I think for young people (high school students) this could be confusing to them. It might lead them to think that the electrostatic force is proportional to 1/r^3, which it is not. For the article to be written for all audiences, I believe it should use the form that I prefer, using a unit vector instead. Comments? -- Dave
I'm basically boycotting TeX -- I didn't participate in "texification" except in a few special cases. See wikitech-l Jan 2003 under "ugly <math>" for why -- I argued that it's ugly, due to being too large compared to the text, but everyone just ignored me and argued against me on all sorts of silly little points while ignoring the obvious issues. Also, you can't wikify TeX like you can HTML -- if it was up to me I would have left the magnetic field formulas like this. Getting back the point, no I don't think there is any consensus, although I wasn't really following the mailing lists back then. Now that the range of TeX displayed as HTML is bigger than it was originally, you can probably use TeX in most cases. -- Tim Starling 06:50 Apr 1, 2003 (UTC)
Ghitis -- your new definition did not use standard physics language, so I reverted it. The electric field is a very well-defined concept in physics, and 'spatial manifestation' and 'material entity' are not. Tantalate 19:57, 26 Aug 2004 (UTC)
I think that both forms are important and that unless there is a good reason not to, the equations should look more like : Most, if not all advanced E&M textbooks include both, and with good reason: there are times when each is advantageous over the other. -- Scott
In my opinion, the most definite and illustrative formulas for the electric field are for the set of point charges and for the continuous charge distribution. These forms emphasize the fact that the field is determined at the point and is caused by either charged particles at points or the charge density in all points in the volume . These formulas were used in the book on electromagnetism by Grant and Philips. What do you think? Do they look too complicated? -- Jmattas 09:58, 8 August 2007 (UTC)
Someone created the page Uniform electric field. I don't think we need a page like that. What do you think? Should it be deleted? Merged with this page? Or expanded into a full article? (What would it talk about?) -- Coppertwig 21:29, 20 September 2007 (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 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 16:31, 6 November 2007 (UTC)
The derivation takes up too much space, and shouln't be at the top. Not only that, most of that derivation is describing coulomb's law which should simply be linked to. I'll do that if noone objects. Fresheneesz 06:46, 3 May 2006 (UTC)
The permittivity of a vacuum is not 'usually 7'. I'm removing that from the Coulomb's Law section. -MrDeodorant, December 15 2007 —Preceding unsigned comment added by MrDeodorant ( talk • contribs) 04:42, 15 December 2007 (UTC)
I added the SI base units to the introduction because I feel it would improve the article. Any objections? Bdforbes ( talk) 21:26, 21 November 2008 (UTC)
The article gives the unit for electric fields as Zoids. I can find no reference to this as a unit of measure equal to N/C. —Preceding unsigned comment added by Omicron84 ( talk • contribs) 02:10, 17 May 2009 (UTC)
It was posted by "Zoidfather", the "Zoid" is not a unit of measurement and appears to have been spam. I've removed it. Hungryhungarian ( talk) 17:32, 21 May 2009 (UTC)
It is very misleading to begin this article with a definition in terms of potentials. Historically, the electric field was seen as an abstraction of the electric force, and the most intuitive definition was through the formula F = q E for static fields. Topics such as elementary particles and vector potentials should be left our or included only parenthetically. 146.6.178.202 ( talk) 17:24, 8 September 2009 (UTC)
I'm not an expert on dimensions. But I think the kg·m·s−4·A−1 unit needs to be revised. Nedim Ardoğa ( talk) 08:10, 13 July 2009 (UTC)
Whatever the dimensions of electric field may be, the SI UNIT is volts/metre. Please correct this .. Andrew Smith —Preceding unsigned comment added by 82.32.50.77 ( talk) 10:23, 3 January 2010 (UTC)
The previous version of the Definition section seemed to be focused on defining electric charges rather than the electric field. I edited that information out and also merged the Coulomb's Law section, since it was essentially defined in terms of Coulomb's Law (and Gauss's Law). I included several common equations that could be used as mathematical definitions of electric field. It might still need a little more cleaning up right at the end, however, but it should be accurate, at least. 71.225.188.211 ( talk) 23:39, 10 February 2010 (UTC) To me it is most obvoius that uncontrolled democracy is undistinguishible from pure chaos. Just listen to this mambo-jambo "In physics, an electric field is a property that describes the space ". Describes what? The space? And further down where the charge q approcahes zero. I am professional engineer and through my entire career I have know that the the probe charge is REMOVED to infinity. And the same with the rest of the .....Lord almighty, where are we going! —Preceding unsigned comment added by Sergei.Borodinski ( talk • contribs) 19:15, 12 February 2010 (UTC)
By Heldervelez: The 'fathers' of electrodynamics believed in an infinite universe in time, but we know now differently. The integration extended to ALL space is incorrect. One can only integrate inside the light-cone, and the E-field energy becames a time growing value, instead of a constant one. To preserve the energy of the entity particle+field the mass of particle must decrease thru time. The killing error is presented here: and discussed at BautForum ATM Links to a new model of the universe based on 'Evanescence' is also presented there. I'm willing to make a reference to this claim as Controversy. Any ideas ? —Preceding unsigned comment added by Heldervelez ( talk • contribs) 18:35, 24 September 2010 (UTC)
For well over 100 years now scientists have been raised to believe that real world stuff can be defined to BE a mathematical models. Example from this article: "The electric field !!! IS !!! a vector field". Wether or not this phenomena IS photons or IS something else from the real world is irrelevant (I personally believe it's a property of spacetime just as curvature is). It is, as the above writer states, "as real as kangaroos" and definitely not a "vector field" which is a mathematical invention nowhere to be seen in the real world. This definition and (many others) need to be changed to something like "a phenomena that can be mathematically represented as" a vector field. —Preceding unsigned comment added by 109.186.43.95 ( talk) 18:22, 13 November 2010 (UTC)
This is unnecessarily verbose - 'The strength or magnitude of the field at a given point is defined as the force that would be exerted on a positive test charge of 1 coulomb placed at that point; the direction of the field is given by the direction of that force.' Since E has been defined as a vector, and force is also a vector, it suffices to say 'E is defined as the force, of electric origin, on a unit positive charge'. Simplicity makes for clarity, I feel. —Preceding unsigned comment added by 82.32.49.157 ( talk) 08:37, 25 November 2010 (UTC)
Main changes:
For those that wrote the article and who I may be insulting: don't get me wrong - its good to add external links and try etc, but better to use secondary sources more than primary. =)
-- F = q( E + v × B) 01:16, 28 February 2012 (UTC)
I reverted these [1] changes as they appear to move away from standard notation. IRWolfie- ( talk) 13:16, 9 July 2012 (UTC)
Definition Problem: The current definition on the page is: "The electric field E is defined as the force F experienced by a stationary positive unit point charge q at position r (relative to Q) in the field". Problem: The Electric field is not a force. It is not even a set of forces. It is a set of forces per unit charge that can be defined by a vector-valued function. The most important change that needs to be made is the part about force per unit charge. By analogy, one can reference gravitational field. One would never say that "The gravitational field G is defined as the force F experienced by a stationary point mass m at position r (relative to M) in the field". The reason is that the gravitational field is not a force. Mathematically, it is a tool for computing any force affected by the field. Here is my suggestion for changing the definition (I use rectilinear coordinates because they are familiar to more readers):
Consider a point charge q with position (x,y,z). Now suppose the charge is subject to a force due to other charges. Since this force varies with the position of the charge and by Coloumb's Law it is defined at all points in space, is a continuous function of the charge's position (x,y,z). This suggests that there is some property of the space that causes the force which is exerted on the charge q. This property is called the electric field and it is defined by
Notice that the magnitude of the electric field has units of Force/Charge. Mathematically, the E field can be thought of as a function that associates a vector with every point in space. Each such vector's magnitude is proportional to how much force a charge at that point would "feel" if it were present and this force would have the same direction as the electric field vector at that point. It is also important to note that the electric field defined above is caused by a configuration of other electric charges. This means that the charge q in the equation above is not the charge that is creating the electric field, but rather, being acted upon by it. This definition does not give a means of computing the electric field caused by a group of charges.
Being somewhat unfamiliar with HTML or whatever, I could not get the subscripts to have a space; It should say "On q", not "On'q". Someone who knows what they are doing should maybe help out with that if they get a second.
Qualitative Description Problem: The qualitative definition makes the same mistake of defining the E field as a force that would hypothetically exist under some condition, rather than force per unit charge, but I am willing to give some artistic license to the qualitative description. My problem is with the last analogy: "...The electric field is to charge as gravitational acceleration is to mass and force density is to volume." I like the gravity analogy, but I have no idea what this is referencing: "force density is to volume". That might be true in some context, but I have a degree in physics and nothing springs immediately to mind. I recommend clarifying the context or just scrapping it because it is confusing. It might even be misleading because definitions of E field often reference space which is not meant in the every-day sense of the word; In mathematics, space is a set of points which is very different than a scalar associated with some set of points (which is what volume is).
I will wait a little and see what people think of this and if I do not get any complaints I am going to change the definition in the article. I have not read the citations in the article, but I have read a couple of other resources (college text books) that I can cite in the article that back up my definition. I suspect that the other sources give accurate definitions, but that they were misinterpreted when paraphrased. — Preceding unsigned comment added by SortOfStillCare ( talk • contribs) 14:26, 26 July 2012 (UTC)
I notice that Special:Contributions/83.131.29.96 has changed magnetic flux density to magnetic field in a number of articles. I am conscious that a blanket reversion could antagonize, but magnetic flux density would seem to be correct in this case. It would facilitate discussion if this user acquired a name. Incidentally, I would agree that the distinction between flux and field could disappear in more advanced treatments using some system of natural units (and in the historical emu system? (I forget)). However, the fact that this article is called Electric field, and not say electromagnetic tensor, suggests a more elementary approach is appropriate. -- catslash 17:56, 7 July 2007 (UTC) hhkjhhgjhighgjih — Preceding unsigned comment added by 12.218.113.146 ( talk) 18:01, 12 October 2012 (UTC)
I've been looking at the section on electrostatic fields, and it is quite messy. Equations seem to be presented out of order (or at least the descriptions of them are out of order). Also, there is an equation derived from Coulomb's Law that is simply in the text and not explained in any way. I don't know where to start to rewrite this section, but it definitely needs some work. K of slinky ( talk) 14:28, 10 July 2012 (UTC)
what is the electric field
electric field is area of charge, whare another charge partical expirinced the force of atreaction or repeltion. — Preceding unsigned comment added by 101.215.149.52 ( talk) 03:20, 15 October 2012 (UTC)
I noticed repeated use of the capital letter theta for electric potential. Besides the fact that I've only seen potential represented by V, I found that the Wikipedia article on potential does not use this notation either. I believe this notation may confuse people who usually see electric flux represented by theta. Does anyone know why this letter may have been used here in this context? ~Username222 ( talk) 01:05, 29 January 2013 (UTC)
The first two sentences here read:
An electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the surrounding force of an electrically charged particle exerted on other electrically charged objects.
I'm curious, what language is that? It has some superficial resemblance to English, but lacks the crucial characteristic of communicating meaning to others who speak the same language. Would someone with some fundamental understanding of the basics of the topic perhaps like to write a couple of sentences that lay out clearly what an electric field is? I believe that would make a good opening to an article on the subject. Just to be clear, we don't need to know what it surrounds (how does it know where the limits of the "time-varying magnetic fields" lie, by the way?), or what it depicts; but it'd be really handy to know what it actually is. Thanks, Justlettersandnumbers ( talk) 00:31, 16 July 2013 (UTC)
can we add that electric field is a model in physics that represent the medium in which charged particles can apply force to each other? because even though electric fields represent natural behavior extremely well the electric field itself does not exist, it an mathematical model. kfir 09:15, 10 September 2013 (UTC) — Preceding unsigned comment added by Comixdude ( talk • contribs)
The electric field is a vector field. The field vector at a given point is defined as the force vector per unit charge that would be exerted on a stationary test charge at that point. An electric field is generated by electric charge, as well as by a time-varying magnetic field. Electric fields contain electrical energy with energy density proportional to the square of the field amplitude. The electric field is to charge as gravitational acceleration is to mass. The SI units of the field are newtons per coulomb (N⋅C−1) or, equivalently, volts per metre (V⋅m−1), which in terms of SI base units are kg⋅m⋅s−3⋅A−1 — Preceding unsigned comment added by 122.144.124.104 ( talk) 03:15, 12 December 2013 (UTC)
In the definition (and in the entire article), A is not defined and I do not understand what it stands for. I think this should be explained. -- Arnaud Dessein ( talk) 12:42, 16 March 2009 (UTC)
It's an SI representation of Ampere SI:
Current (1946): The constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2×10−7 newtons per metre of length. Mwasheim ( talk) 19:48, 9 April 2014 (UTC)
There exists an article called electromagnetic field. And yet another called electromagnetism that describes the EM interaction (the EM fundamental force).
So what are these articles about the electric field and the magnetic field? They are just articles about the electromagnetic field when seen by a privileged observer-- one who misses one field component because he's positioned just right in space and time.
That's like looking at a cube from JUST the right angle to see a square, where any other place when show you a 3-D object. There isn't any PLACE that "has" an electric or magnetic field. Because any observer at such a place simply needs a velocity and will no longer see a pure E or B, but a mix. So it's both a place AND an inertial frame that seems to have just one field. So even though you can imagine an E field in a given place and frame, if you move, it's all screwed up and now you have both E and B.
There is an analogy with kinetic energy: if you hold position with regard to an electron, you will just its E field. And you ALSO will see no kinetic energy of the electron. But if it moves, or if it stays the same place but YOU move, you will no longer see just an E field, but now you see a new B field, and (moveover) also see that your electron "has" kinetic energy.
So is a "pure" E field "real"? Is it even worth the long discussion here? If the E field from a distant particle is no more real than the kinetic energy of that distant particle (which comes and goes, depending on how you look at it, and what frame you look at it), then how real is that? S B H arris 05:42, 31 July 2013 (UTC)
E-fields are just mathematical abstractions? No. Since the time of Maxwell we have known that e-fields and b-fields are two facets of electromagnetic fields and they contain electrical energy. E. g., if a positive charge is pulled away from a negative charge, energy is stored in the surrounding e-field pattern. (A mathematical abstraction cannot store electrical energy!) In modern QM and Gauge theory, we regard the classical fields as being caused by photon exchange, both magnetic fields and electrostatic fields are "made" of photons.-- Wjbeaty 11:22, Feb 28, 2005 (UTC)
I like Wjbeaty's example. I've come to realize that gravity cannot create energy but it can store energy. From this I'm trying to learn about radiation energy and momentum energy. In my study, radiation got me to electromagnetic radiation, which got me to electric field, which got me here. But, except for the one example by Wjbeaty, not much seems easy to understand. I think things should be explained using the least amount of complicated terms as possible. Not pointing fingers, but people often try to showoff their knowledge by using complicated terms that just make it impossible to understand an idea. Of course the complex formulas are great and needed for practical purposes. But before I get to those I need to understand what an electric field is, how it is created, what it affects, etc. I did learn that an electric field is always accompanied by a magnetic field but how it relates I'm still not sure. Of course, perhaps I just didn't try hard enough to understand so this is just an opinion that may or may not help improve this page in the future. Darcy MacIsaac 63.135.12.196 ( talk) 20:14, 9 July 2014 (UTC)
Is this ever called E-field? I would like to replace "In physics, an electric field or E-field" with "In physics, an electric field (also known as an electrostatic field)" since 'electrostatic field' is very common usage (I just saw it in the wikipedia requests and redirected to this page) Shameer 03:12, 14 Feb 2005 (UTC)
In physics, we always called 'em by the names "e-field" and "b-field." The phrase "electrostatic field" has too many syllables for convenient use in heated late-night conversations! Search google for e-field: 149,000 hits, while "electrostatic field" gets only 75,000 hits: [2]
In the definition section there is the phrase:
This definition does not give a means of computing the electric field caused by a group of charges.
I don't think this is true since the assumption of point charge was never made. I suggest to remove that line.
AsafPM ( talk) 19:12, 6 November 2014 (UTC)
Hello to all,
I have been WP:BOLD and edited the article heavily ( diff of my changes).
I removed a lot of things on my way, hopefully it contains less gibberish now, but valuable content that I did not recognize as such might have been lost. There is still a huge need for inline citations. Picture would be valuable.
If you do not feel like editing but still would like to mention something that is not right, please do.
I will change the issue template at the top of the page to reflect what I expect to have done, but feel free to put it back in place if you think it still belongs there. Obviously, I am not the best judge of my own edit-orgy.
Tigraan ( talk) 15:13, 24 December 2014 (UTC)
The current into paragraph is:
"The electric field is a component of the electromagnetic field. It is a vector field and is generated by moving electric charges or time-varying magnetic fields, as described by Maxwell's equations.[1] The concept of an electric field was introduced by Michael Faraday.[2]"
Which I believe can be better understood if reworded as follows:
The electromagnetic field is a spatial vector field which is generated by moving electric charges or by time-varying magnetic fields, as described by Maxwell's equations.[1] The electric field,(this article) which is one component of the spatial vector field, is perpendicular to the other component of the spatial vector field, which is the magnetic field. The concept of an electric field was introduced by Michael Faraday.[2] — Preceding unsigned comment added by DPHutchins ( talk • contribs) 08:03, 29 February 2016 (UTC)
I'm pretty new here, but I'm trying to help make the electromagnetics articles less messy and more readable. I notice there is a separate article (a stub) for electric field intensity. It should be removed, and instead pointed here, right? I'm adding mention of that term to this page, in addition to some other readability changes. Please let me know if I do anything bad! Xezlec
I disagree with the use of the term "electric field intensity" in referring to the electric field vector. Traditionally the term intensity refers to the modulus squared of the electric field (or the square of the electric field strength to use the terminology in the article). Intensity is a scalar quantity, not a vector. Regards, Justin Hannigan.
same. Regards Sevil Natas — Preceding unsigned comment added by 58.106.66.223 ( talk) 10:54, 10 October 2017 (UTC)
Hi Jennica. I can't figure out my "Talk" system. So not sure if this will reach you. Have you noticed what I've been doing? I haven't since October 28 changed anything in the body of the subject discussion. I have added references (as you guys have asked for) from one of the most popular and long time university texts on the subject of Electricity and Magnetism: Edward Purcell PhD, University of Cambridge, 820 pages. Also from professor Browne's book. These are very appropriate footnotes to the various subject paragraphs and reinforce those subjects plus I have quoted what they wrote. There could be more over time. But block me if you wish. John DeVore e-mail: jw@jwdevore.com — Preceding unsigned comment added by 73.81.156.127 ( talk) 17:40, 31 October 2017
HEY EDITOR: In the past two days I have tried to add very applicable reference sources to four similar and related wikipedia electromagnetic articles, the bulk of which at even with the first introduction paragraph are baffling to anyone but a graduate scientist. Definitely I'm not attempting to vandalize. Rather than lead off "ELECTRIC FIELD" with Feynman's accurate but novice baffling discussion of an electric field using terms like Coulomb and infitestimal particle not already defined or explained, how about leading off with two or three sentences that provide the novice an image in his mind of wat is to come? How many non-science types know what a "charge" is? Some, sure, but EVERYONE has a mind picture of an electron whirling around in his high school science class molecule video. So, start with an electron in the first paragraph, call it a charge from here on, and discuss the fact that this electron "charge" has a field surrounding it which it creates. And that affects everything around it. By a FORCE. Or as reference professor Browne (page 225) says, a charge has an "aura" around it. Then the paragraphs following can get more complex (after all, it IS a complex subject) and can bring in a sea of integrals and other equations which stop most people cold in which they then stop reading and go on and look something else up. I'm a retired electrical engineer who had a few college courses in electrodynamics and radio transmission theory and was very lucky to get Cs in those curve busters and am trying NOW to get a better grip on the subject. Oh, and just try to figure out the REFERENCE and NOTES and OTHER READING system of WIKIEDIA. Its as confusing as Gauss. John DeVore, Doylestown, PA, jw@jwdevore.com — Preceding unsigned comment added by 73.81.156.127 ( talk) 20:46, 28 October 2017
Please explain better the distinctions between the terms electric field, electric field intensity (magnitude of the electric field vector) (E) ( V/ m), electric field strength (vector quantity), electric field gradient, E-field, and so on. What are the units of each? - Omegatron 13:16, July 19, 2005 (UTC) I'm pretty new here, but I'm trying to help make the electromagnetics articles less messy and more readable. I notice there is a separate article (a stub) for electric field intensity. It should be removed, and instead pointed here, right? I'm adding mention of that term to this page, in addition to some other readability changes. Please let me know if I do anything bad! Xezlec
Okay, I went ahead and did the above-mentioned redirect. This is ok, right? Xezlec 04:11, 31 December 2005 (UTC)
Sorry for continued nitpickery. I've now expanded the article to mention that a changing B-field also produces an E-field. I revised some things to make it clear that most of the rest of the article applies only to the static case. I'm not sure the overall structure of the article is still "pretty-looking" but at least it's more complete and more strictly correct now. Xezlec 06:45, 31 December 2005 (UTC)
I disagree with the use of the term "electric field intensity" in referring to the electric field vector. Traditionally the term intensity refers to the modulus squared of the electric field (or the square of the electric field strength to use the terminology in the article). Intensity is a scalar quantity, not a vector. Regards, Justin Hannigan.
Smythe's "Static and Dynamic Electricity" refers to E (the vector) as "electric field intensity". Also see Marion + Heald, p3, which calls it "electric intensity vector or electric field vector". Pfalstad 19:18, 26 September 2006 (UTC)
I agree with Justin Hannigan. The standard terminology is simply electric field.--24.52.254.62 06:21, 3 November 2006 (UTC)
The term "E-field" currently occurs in the lead sentence of two sections of the article, but is nowhere defined. The reader is left guessing whether it means "electric field", as might be inferred by the frequent use of that term in the preceding sections. The term "E-field" should either be defined early in the article, or replaced by a term that has been defined. — Wdfarmer ( talk) 20:27, 25 September 2018 (UTC)
An anonymous editor added some text [3] including the words:
This gives the impression that the article is arguing with itself. Can anyone think of a better way of putting it? The wording of that whole edit could be clearer. Thanks. -- Heron 22:36, 2 July 2005 (UTC)
Field intensity is not mentioned in the article. Does that mean they are the same? — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 16:52, 28 February 2020 (UTC)
The electric field is a vector field. That is to say, every point in 3-dimensional space has a vector attached to it that contains the direction and magnitude of the electric field at that point in space. So you can say that E = {E_x, E_y, E_z}. The direction of the electric field is contained in this vector due to the relative magnitudes of E_x, E_y, and E_z. The magnitude of the electric field is found by using the Pythagorean theorem in 3D, or |E| = sqrt(E_x**2 + E_y**2 + E_z**2). Also, in pictorial representations of the electric field, the density of the lines will generally correspond to the intensity of the field. Footlessmouse ( talk) 22:42, 12 August 2020 (UTC)
Although MUCH better in its introduction and general organization than than the Wikipedia article "Magnetic Field," this Wikipedia article Electric Field can only be understood (and that only maybe) by someone who already has a PhD in physics. It is worthless to the uninitiated, yet the uninitiated are those who you want to use Wikipedia as an encyclopedic information source. — Preceding unsigned comment added by 108.36.71.119 ( talk) 23:05, 19 March 2020 (UTC)
My sugestion would be tat teintroductoryparagrap be much briefer. Maybe just a few sentences. Then the next heading be "What is a force field" A few sentences to explain this. Then the next "What is a charge." Then "What is a magnetic field (and also an Electric Field) even though yoone can't see it." That is the probem to the uninitiated: this subject can't be seen, can't be felt unless one has iron fillings in their mouth (ha!) , but it must be conceptualized if to be understood well while being taught. Equations provide no mind conceptualization ecept to the math major or the physics major I realize tyat I am not making a whole lot of sense here. Mabye an opening paragraph should be "Magnetic Fields for Dummies." J Devore, Doylestown PA. retired antenna designer still trying to fully grasp the subject! (I once told a colleague that a flashlight was an electromagnetic radiation antenna device and got an argument that tapered off as he thought more about it. Yeah, we can SEE the stuff in one part of the EM spectrum. Thus extrapolate what we see into the spectrum we can't see where we are trying to pat down those projections in the antenna's radiation pattern to get all of the power forward for efficiency and also for reducing to the side detection by opposition forces.) — Preceding unsigned comment added by 73.81.156.48 ( talk) 14:05, 21 March 2020 (UTC)
I think we could do a better job of linking to other pages that have the space to explain core concepts better than we can here. If we need to add a section that avoids vectors, I could write a section for a one-dimensional electric field, though it would not add any substance to the article. I do not believe we can dumb down the definition section very much, in fact it should be generalized as it is very static-oriented. Also, a vector field (or force field in general) cannot be defined without reference to vectors and vector calculus. I think it is easier to teach people about the electric field by starting with the potentials and simply taking the gradient and curl of the scalar and vector potentials (and most people know what voltage is, and its a short explanation to teach them potential difference is the difference between the electric potential at two points in space). All of these would link to other pages so as to make this article more concise. We could reword the introduction to include the term force field, which can link to the article and we can defer explanation of what a force field is to that page. The gravitational field article opens as "In physics, a gravitational field is a model used to explain the influence that a massive body extends into the space around itself, producing a force on another massive body." Which I think is pretty good, we could start with a morph of this, like "In physics, an electric field is a force field used to model the influence that one electric charge extends into the space around itself, producing a force on other charges." And go from there, but the wording is still very tricky and that only includes static electric fields. I think one of the key points is that the electric field is a model that physicists and engineers use to quantify the dynamics of charged particles in the presence of a charge or current distribution, it is very mathy and, as a model, has very little applicability to everyday-life. Electronics and electricity and static electricity and many other articles can be linked to for more nontechnical information on the subject. Footlessmouse ( talk) 23:05, 12 August 2020 (UTC)
It would be easier for people to understand if we used a couple of sentences to describe the equations, but it is usually unsatisfying. For instance, I can replace the first sentence of the definition section with
But that is convoluted and it is hard to fit all the details in there and is a pretty bad run-on sentence. Regardless, when the equations make sense, then everything else (mostly) makes sense, so some effort should maybe be spent in making the equations less daunting (across the EM articles). Footlessmouse ( talk) 11:48, 13 August 2020 (UTC)
I object to User:85.2.30.77's recent removal of the picture of a cat with styrofoam peanuts stuck to its fur. This article is very abstract and desperately needs examples of the effects of an electric field in everyday setting for nontechnical readers, and this picture was the only one. Your explanation was the picture was "inappropriate for the context". In what way? As explained in the caption, the styrofoam is held on by the electrostatic field of the charged fur. -- Chetvorno TALK 20:05, 3 August 2020 (UTC)
The cat picture and caption failed to add anything to the article and existed only to confuse readers as to the nature of electric fields. I could just have easily taken a picture of a battery, lamp, computer, cell phone, television, remote control, or anything else electronic and stated that it is proof of an electric field. The statement is incoherent as it requires a great deal of work to see how these phenomena are, in fact, related to the electric field. The same picture and caption are available to view in the static electricity, where it is much more appropriate, as it is an example of static electricity in real life (though, for the record, I strongly object to all frivolous pictures of everyday life examples of electricity in these articles, that is how youtubers and tv shows explain science to children, Wikipedia is an encyclopedia and encyclopedias do not include frivolous examples of phenomena and they certainly do not offer them as "proof" of anything). The figures currently in the article that depict lines of electric flux are the only pictorial representation of the electric field that are relevant to the article. While it may be a great illustration of static electricity, this illustration makes it harder to explain the ideals that underlie the electric field as a whole, as it is a very, very special case of a very general phenomenon. I also do not believe we need to include examples of the effects of the electric field in everyday settings. That is a job for the electronics and electricity (and static electricity) articles. Maybe we can link to them? The electric field is, manifestly, a mathematical means of calculating the effects of distributions of charge, it is not useful for laypersons and has no applicability to everyday-life. I think we should do a better job of pointing to the other articles related to electricity and electric charges so nontechnical readers can follow those links to find more relevant information. Footlessmouse ( talk) 22:20, 12 August 2020 (UTC)
Can we get a 3rd opinion? I will leave the new picture of the girl there for now. Lacking a discussion on the merits of these pictures, by anyone but us, we may have to use arbitration to determine whether they are appropriate. — Preceding unsigned comment added by Footlessmouse ( talk • contribs) 20:46, 13 August 2020 (UTC)
I disagree with Footlessmouse's position here. This is a physics article. If you reach the point where you are asserting that the concept under discussion is purely a "mathematical model" that cannot even in principle be illustrated with a physical example, you've left the bounds of physics altogether. Ultimately models in physics must connect to the physical world, and it's useful to illustrate that connection.
I do prefer the image of the girl to the one with the cat. It more directly illustrates the effect of the electric field: a force exerted on charges by other nearby charges.-- Srleffler ( talk) 23:40, 13 August 2020 (UTC)
Thank you all for your input. It seems as if everyone is either neutral or wants to keep the pictures and it doesn't seem to explicitly break any policies and so withdraw my objection to the new photograph. Footlessmouse ( talk) 04:41, 14 August 2020 (UTC)
To address complaints about the technical nature of the article and also as a partial compromise with @Chetvorno over the cat and girl pictures (see above) I propose we create a new History section that goes above the definition. It will link to a main article History of electromagnetic theory. This will bring it more in line with pages such as the magnetic field and will give nontechnical readers a chance to learn why we use the electric field, from a historical perspective. Then the math that follows is just a generalization of that. This section can include some pictures of the effects of the electric field, as they were discovered historically. I could write a draft of the new history section in the next few days if anyone likes the idea. I, otherwise, object that it is overly technical and overly written and requires a PhD to understand. Many physicist will object to the way many parts of the article is written, as it is simplified at every stage. In the definition section, it is only valid for the extremely unrealistic case of an equilibrium charge distributions in a vacuum, so that all the charges feel a force due to all the other charges, but none of them, save an imaginary test charge, ever move. That is to say, it could, and maybe should, be more technical, not less. We just have to find a way to explain it better. I think a history section may help. Footlessmouse ( talk) 01:02, 14 August 2020 (UTC)
Hi all, reading through other articles, I found electricity#Electric field. It seems to me that the introduction on that page is far superior to the lead of this article and could be used to clean this article up considerably. The introduction there is aimed at nontechnical readers, is well-written, and is easy to understand. It does a good job summarizing the electrostatic content in this article. It also includes some history in it. I believe this, and the proposed history section, is the place to start for trying to make this article more nontechnical friendly. Footlessmouse ( talk) 23:51, 17 August 2020 (UTC)
I have come up with the following as the first sentance of a history section
I find trying to write a history section quite difficult, as it should be short but representative. I am not a historian of science and I find it difficult to pick and choose whose contributions are most important and wothy of mention. (outside the lucky few who get their names attached to equations we still use - i.e. Coulomb, Maxwell, and Faraday). I will think about it more. Neither Griffith nor Jackson provide a satisfactory summary on the history (not that they should have), but I adapted that bit from Jackson's intro. Footlessmouse ( talk) 10:19, 20 August 2020 (UTC)
References
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@ DVdm: I see your justification for rolling back the anonymous user's edit, but I am 99% sure they were right. I am at a loss for finding it in a textbook at the moment, but wanted to send a message to let others know in case they happen to know where to look and can find a source more easily. Footlessmouse ( talk) 09:59, 11 October 2020 (UTC)
Okay!!! I feel dumb for not checking here as one of my first stops, but Landau Lifshitz Electrodynamics of Continuous Media (1963) §68 the propagation of waves in an inhomogeneous medium. "In Maxwell's equations… ε is a function of the co-ordinates." p. 285. Like virtually all physics texts, the book continues to leave it as implicit in the equations:
But this is a reliable source that allows us to at least fix up the text around it. Maybe just drop the explicit functional dependence on position from the whole expression and explain it in text. @ DVdm: Any thoughts? Footlessmouse ( talk) 19:25, 11 October 2020 (UTC)
I'm late to this party, but I think writing is highly misleading. The field is always going to vary according to the geometry of the system. Permittivity is nominally constant, varying with position only when the medium is explicitly inhomogeneous. In some materials it will also vary with field and direction (non-isotropic material). Conceivably, it can vary with time, for instance in a liquid medium where the concentration of a solute is changing, or in a solid that is deteriorating. So would you want to write for completeness? I don't think so; doing so detracts from the essence of the relationship. There's a reason you are struggling to find a textbook that states things this way. Spinning Spark 11:58, 18 October 2020 (UTC)
I think it would be worthwhile for editors knowledgeable in this area to start a section on the commercial, scientific and any other applications of electric fields. -- 147.10.208.4 ( talk) 06:36, 31 January 2021 (UTC)
"the electric field E is referred to as the optical field" fgnievinski ( talk) 03:03, 13 May 2022 (UTC)