Talk:Electric field/Archive 1

Archive 1

Archive 2

list of Efields due to common charged surfaces

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)

change to first line

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)

r^3

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

Done. Dave is right, it is confusing with r^3. Of course, some readers may not understand what the hat means, and finding out isn't very easy, but that's alright. Maybe someone can make a note of it in the text (though that might require inline TeX :P ). The reason I didn't do it this way to start with is that the formulas were written before TeX came along: there wasn't really any way to make a hat. Do you think the vectors should be on the top of the fraction, or outside the fraction like I just did it? -- Tim Starling 05:38 Apr 1, 2003 (UTC)

Thanks. I'm glad someone else prefers it this way. It is nice to look at a formula and right away see the dependency that you care about, without having to think about the vector. BTW, I like the vector "outside" the \frac like you did it. Very clean, separates the magnitude part from the vector part. Totally unambiguous. --dave

p.s. Do you know if we are supposed to be using TeX for everything? I read the page about Wiki mathematics or whatever, but it sort of left the issue up in the air. It said that TeX is bad for inline due to the weird line heights it creates, and it is slow for web pages to load and text browsers can't see it. But it's so easy to write in TeX style. Is there any consensus?

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 :$\mathbf {E} ={\frac {1}{4\pi \epsilon _{0}}}{\frac {Q}{r^{2}}}\mathbf {\hat {r}} ={\frac {1}{4\pi \epsilon _{0}}}{\frac {Q}{r^{3}}}\mathbf {r}$ 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

I second this, as a brief look at the history shows that people have been twidling the $r^{2}$ to $r^{3}$ periodically, not realizing that ${\hat {r}}$ already is a unit vector. —The preceding unsigned comment was added by 128.61.117.118 (talk) 02:35, 11 February 2007 (UTC).

In my opinion, the most definite and illustrative formulas for the electric field are $E(\mathbf {r} )={\frac {1}{4\pi \epsilon _{0}}}\sum _{i}{\frac {q_{i}}{|\mathbf {r} -\mathbf {r} _{i}|^{3}}}(\mathbf {r} -\mathbf {r} _{i})$ for the set of point charges and $E(\mathbf {r} )={\frac {1}{4\pi \epsilon _{0}}}\int _{V}{\frac {\rho (\mathbf {r} ')dV}{|\mathbf {r} -\mathbf {r} '|^{3}}}(\mathbf {r} -\mathbf {r'} )$ for the continuous charge distribution. These forms emphasize the fact that the field is determined at the point $\mathbf {r}$ and is caused by either charged particles at points $\mathbf {r} _{i}$ or the charge density in all points $\mathbf {r} '$ in the volume $V$. 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)

Ah, Jmattas, that's exactly the form I was looking for, myself. I am struggling through reviewing from a textbook I haven't read in a long time (Griffiths' Introduction to Electrodynamics), and your "illustrative formula" reminded me that my professor simply never used Griffiths' "script r" but instead always used its definition: "script r" = $\mathbf {r} -\mathbf {r'}$.

Now, you ask if it looks more complicated using that in the formulas... I'm not sure. Something must be done to ensure the greatest clarity, and I liked Scott's idea of showing two forms of the same expression, because it is indeed true that there are different reasons to use each one. --Qrystal 22:22, 18 September 2007 (UTC)

Uniform electric field

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)

Template:Electromagnetism vs Template:Electromagnetism2

I have thought for a while that the electromagnetism template is too long. I feel it gives a better overview of the subject if all of the main topics can be seen together. I created a new template and gave an explanation on the old 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)

Derivation

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)

Speed of propagation for gravity

Comparing gravity with electrostatics, the article states that "both propagate with finite speed c." Is there a reference for this? As far as I know in the Newtonian mechanics gravity propagates instantaneously? If so this statement needs to be put under differences. Zeyn1 (talk) 20:22, 26 April 2008 (UTC)

General relativity, which supersedes Newtonian mechanics, predicts that gravity propagates at c. - Eldereft ~(s)talk~ 01:07, 27 April 2008 (UTC)

The article states that we are talking about the similarities between electrostatics and Newtonian gravity: "Coulomb's law which describes the interaction of electric charges is similar to the Newtonian gravitation law." So the statement "both propagates with finite speed c" means that Newtonian gravity propagates with the speed of light. The article on the speed of gravity is clear that Newtonian gravity is instantaneous. I propose that this item be moved to the differences between electrostatics and Newtonian gravity. Zeyn1 (talk) 16:58, 29 April 2008 (UTC)

You are right, I misread the section. Rather than moving it to differences, I think it would be more pedagogically useful to clarify that in GR they both move at c. - Eldereft ~(s)talk~ 17:11, 29 April 2008 (UTC)

SI base units in introduction

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)

Thanks to whoever corrected the units I put in... not sure how I got that wrong, must have been tired. Bdforbes (talk) 23:20, 23 November 2008 (UTC)

Units

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)

Definition?

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)

The unit

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)

At the beginning of the article, I see both N/C and V/m listed as equivalent SI units for electric field, which is correct. Is there somewhere else where the wrong SI units for electric field are given? CosineKitty (talk) 15:23, 3 January 2010 (UTC)

Rewrote definition section

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)

Fundamental Error in the calcul of Energy of E-field

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)

Mathematical Fields are only models of the physical world

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)

Further rewriting desirable

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)

This article is BLECHH...

Main changes:

• "Therefore an electric field is defined with respect to a particular configuration of source charges." <--- Correct.
• "In practice, this is achieved by placing test particles with successively smaller electric charge in the vicinity of the source distribution and measuring the force exerted on the test charges as their charge approaches zero.

$\mathbf {E} =\lim _{q\to 0}{\frac {\mathbf {F} }{q}}$

This allows the electric field to be determined from the distribution of its source charges alone." <--- This is simply a meaningless definition that I have yet to see in use anywhere (feel free to contradict with examples). No suprise there is no referance. Why take the limit that charge becomes zero when E is force per unit (positive) charge?? Just how does it define the electric field as a config of charges when there is no dependence on position?? All that needs to be said for a defining equation is $\mathbf {E} ={\frac {\mathbf {F} }{q}}\,\!$, where q is a test charge, not a source charge Q. Using Colombs law, the E field due to the source charge Q is $\mathbf {E} ={\frac {\mathbf {F} }{q}}={\frac {Q}{4\pi \epsilon _{0}|\mathbf {r} |^{2}}}\mathbf {\hat {r}} \,\!$. I have also changed the obscure notation "q_t" and "q_s" to be the simpler and more common q, Q.

• The volume integral looks painfully vague
• Clean up the equations
• Re-write for less wordy prosy sentences, made them to the point, remove a lot of repetition
• Re-section in places
• Moved the current "referances" into the external links and replaced referances with proper books on electromagnetism.

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)

Changes

I reverted these [1] changes as they appear to move away from standard notation. IRWolfie- (talk) 13:16, 9 July 2012 (UTC)

Error in Definition of E-field and Problem in Qualitative Description

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):

Proposed Change:

Consider a point charge q with position (x,y,z). Now suppose the charge is subject to a force ${\vec {F}}_{\mathrm {On'q} }$ 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, ${\vec {F}}_{\mathrm {On'q} }$ 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

${\vec {E}}(x,y,z)={\frac {{\vec {F}}_{\mathrm {On'q} }(x,y,z)}{q}}$

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.

End Proposed Change

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)

B

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)

Electrostatic fields section

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)

Use of Theta for Electric Potential

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)

First two sentences

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)

I agree. I've reworded it a bit – still not perfect, but hopefully better. — Quondum 02:39, 16 July 2013 (UTC)

Thanks; and yes, I believe it is improved. What I would like to see there and do not have the background to write myself is a simple statement in very plain English of what an electric field is. It seems to me that if the opening sentences of the Qualitative description were simplified, they might fulfil that function. It's a vector field; it represents the magnitude and direction of the force that would be felt by a unit charge placed at each point within it ... but, as must be obvious, I don't have the background. I may be way off here, but it's my feeling that the first few sentences in this sort of article should be accessible to the general reader, with the technical stuff coming further down the page. I should also apologise for the unduly scorbutic outburst above. Justlettersandnumbers (talk) 00:10, 18 July 2013 (UTC)

You are quite correct: accessibility in the lead should be striven for, and in this case should not be too difficult to achieve. And you communicated the shortcoming quite effectively; I found it quite humorous, especially when reading the mangle of words in the quote. It is all in the interests of improving Wikipedia. — Quondum 02:42, 18 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)

To say the electromagnetic field does not exist is not correct in the modern way of thinking about it, and the elecric field is a component of this. You seem to feel that it is really just an action at a distance (much like Newton's concept of gravity), but it exists as a physical entity as much as anything else does. Ask yourself: does light exist? So it is not that clear what you really want. — Quondum 19:49, 10 September 2013 (UTC)

electric field

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)

A

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)

The lede problems above are not the half of it

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? SBHarris 05:42, 31 July 2013 (UTC)

I tend to agree − there are a number of articles in this group of articles that should be merged into fewer articles. The current state is rather confusing, with heavy overlap in content. Maxwell's equations and Magnetism are others in the group. — Quondum 11:32, 31 July 2013 (UTC)

I also agree. However, the solution known to me is Feynman's 2 year introduction to physics which, albeit never neglects the framing, is somewhat lengthy (the first mention of the electromagnetic field and it's definition in is volume one and a proper 'field' definition is in volume 2). I had to return to the Feynman lectures to make any sense of this article. The statements of equations (maxwell/coulomb) in Feynman, even the 'complicated' form preceeding his vector field forms, is readily understood. Admitadly, because he tears those definitions down for the reader to explicitly detail the origin of the component terms (and add caveats along the way). How do we arrive at the narrative qualities of Feynman (for instance, he's not the only one) without a 'section' editorial for electromagnatism. To complicate matters, how to keep from discussing mechanics (which occurs often in Feynman, for instance when introducing 'flux' in the electrical field). On the other hand we distinguish between the electrical field and magnetic field to arrive at the force, F = q(E + v * B ). But, before I start quoting, Feynman demonstrates just why it IS useful to discriminate in, for instance, section 1-2 of volume 2. Mwasheim (talk) 20:15, 9 April 2014 (UTC)

Oh, dear. Just read Maxwell's Equations and found that was much more concise way of resolving my problems with this article. Hmmm. I'm just muddying the waters. In any case, I found Maxwell's usable but Electric Field confusing. Mwasheim (talk) 20:41, 9 April 2014 (UTC)

E-field

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)

Yes I agree, the article should make it clear that these fields are real, and are not just mathematical abstractions. Actually I have a great quote from a lecture David Griffiths (physicist) gave a little over a year ago (spring 2006) "[electric] fields are real, just like kangaroos!" Perhaps someone else might know how this idea should be injected into the article, and if you would like I can properly reference the quote later. Fieldworld 19:11, 24 March 2007 (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]

An electrostatic field is an electric field that doesn't change with time, it's not a synonym. -- Tim Starling 01:51, July 22, 2005 (UTC)

Definition misleading

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)

The quote you give is correct, the definition is not the way to compute the E field given a distribution of charges and currents, you have to solve Maxwell's equations. So rather than removing the line, I'll add the point about Maxwell's equations. Cheers, M∧Ŝc²ħεИ_τlk 08:55, 7 November 2014 (UTC)

Heavy editing (dec. 14)

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)

New Introductory Paragraph

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)

Hello DPHutchins and welcome to Wikipedia! As I see your comment has been signed by a bot, I assume you are new here, and I kindly encourage you to read this help page, in particular the parts about signing and indenting comments.

I personnally disagree with your proposed reformulation, both for stylistic reasons (the former is more clear) and content reasons (E and B are not generally perpendicular, though it is the case for plane waves). Still, I encourage you to be bold and make changes that you feel improve the articles (even if they are reverted, i.e. cancelled, by another editor later) for the next time. Tigraan (talk) 12:12, 1 March 2016 (UTC)

The current version is better, and if I were going to improve it I would do so by removing or delaying mention of the electromagnetic field. The lede needs to start off by talking about the subject of the article (electric fields), not some other topic. Talking about electromagnetic fields is not helpful for a reader who does not understand the electric field. As Tigraan points out, your version is also factually incorrect; the electric field is not always perpendicular to the magnetic field. Note that electric fields can and commonly do exist in the absence of magnetic fields.--Srleffler (talk) 20:30, 6 March 2016 (UTC)

Terminology cleanup

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.

same. Regards Sevil Natas — Preceding unsigned comment added by 58.106.66.223 (talk) 10:54, 10 October 2017 (UTC)

Jennica message to me

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

Hello, John. Sorry that you have not been getting helpful responses here. Your message here is the correct way to voice your concerns; the only other thing you need is a signature, which you add by typing four tildes (~~~~) at the end of your message. I have done it for you this time, and I will also add your comments that were deleted from the article. See the talk page guidelines for more detail on using talk pages.RockMagnetist(talk) 19:53, 6 November 2017 (UTC)

Oh, and you don't need to add your name and email. If you'd like to acquire a Wikipedia identity, you could create an account. RockMagnetist(talk) 20:08, 6 November 2017 (UTC)

Comment moved from article page

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

Joh, thank you for your comments. You're right that the article, including the lead (which is what we call the material before the table of contents), could be made more accessible, and that starting with a more physical description involving electrons or other charged particles would be a good way of approaching it. I would stay away from fuzzy terms like "aura", though. You should be aware, too, that changes to the lead are much more likely to result in battles with other editors than changes to the body of the article (the stuff below the table of contents). As for mastering Wikipedia style, there is indeed a learning curve. Have a look at the links in my welcome message on your talk page. I also recommend looking at some of the best articles like photon and opening them in the editor to see how they accomplish various tasks. RockMagnetist(talk) 20:06, 6 November 2017 (UTC)

Hi, John, thanks for your efforts. I agree the lead paragraph could be made more understandable for general readers. However I agree with RockMagnetist's comments above. I am not sure that 'electron' is a more familiar concept for readers than 'electric charge'; maybe the electron could be used as an example of electric charge. Also I think the sentence: "This is the very powerful physical force that tightly holds all matter together." is too ambiguous. I'd prefer something like: "On a microscopic scale, the electric field is the attractive force between the atomic nucleus and electrons that holds atoms together, and is the force between atoms that is responsible for chemical bonding." Also, the word "Feynman" should be removed from the introduction; you can source your sentences by putting an inline WP:citation such as <ref>Feynman, R. P.; Leighton, R. B.; and Sands, M.(1965) The Feynman Lectures on Physics, Vol. 1, Addison-Wesley, p. 114</ref> at the end of the sentence. This will make the source appear in the "References" section at the bottom of the page. Even better is to use a WP:citation template. Cheers, Chetvorno^TALK 22:02, 6 November 2017 (UTC)

clarification of terms

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)

I agree. I defined "E-field" in the lead sentence, and I also removed it from the rest of the article. The use of this abbreviation is not worth any confusion it might cause to readers. Thanks, Wdfarmer --Chetvorno^TALK 22:33, 25 September 2018 (UTC)

Clarification please

An anonymous editor added some text [3] including the words:

The above paragraph is perhaps misleading ...

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 strength or field intensity?

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)

An over written mess

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)

Thank you for the feedback! I pretty much agree with you, and I wrote some of the stuff you are complaining about. A good part of the article inevitably has to be mathematical, because that is how the electric field is defined and used. But most people coming to this page will be general readers who want a nontechnical explanation, and as you say they are the ones Wikipedia should be written for. I suggest as a first step, the technical "Definition" section should not be the first section of the article. There should be some kind of descriptive or overview section explaining electric fields and their importance in ordinary language. Do you think that would help? --Chetvorno^TALK 15:57, 20 March 2020 (UTC)

Hi:I mot=re than realize that the subject of fields is difficult to understand, let alone to explain. But a teacher must initially place himself outside his box of "I've been doing this for years thus I toss terms around (lines of force, webers) like they are known by everyone" knowledge base in which he makes bad assumptions about the ability of those he is talking to. In my University of Delaware second semester sophomore year (the 21 unit nightmare "weeder" semester) course on Electricity and Magnetism (it got worse with the next course: Electromagnetic Radiation: UHF, VHF.) the instructor opened first day, first minute with a statement about the magnetic field being a force field. He was immediately stopped by someone asking, in effect, what the heck is a FORCE field? He was startled, but then backed up to explain that "a thing" can be in an environment where the "thing" has a push on it. That makes it want to move. Like an elephant with a wind pushing its side. A wind field. Now, he said, take an electron, a charge, sitting in an electric field or moving in a magnetic field. An then he explained how those fields were created, the magnetic one being an easier to mentally image than the electric field. The elephant thing, though ridiculous, immediately provided a mental image to us students, and with that, he was able to build upon how a magnetic field can produce a push on a charge within its field. And begin to add in the math. Terribly simplistic, an elephant, but it was a start for a bunch of 20 year old novices to this strange can't-be-seen new world. Our physics for engineers course hadn't introduced us to force fields nor any discussion of atomic physics and "charges" let alone "forces on charges" and then Coulomb's Law. I only got that stuff in graduate school at UCLA, and it was a learning step function there. (My engineering physics course concentrated on ladders leaning against walls, and optics.) I'm just saying that a Wikipedia article must start small and build. PhDs arguing technical semantics and trying to show off their brilliance really mess things up with their article changes for the uninitiated. But, I agree, this is one tough subject to explain. — Preceding unsigned comment added by 108.36.71.119 (talk) 23:55, 20 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'm afraid that we couldn't take up a lot of your suggestions. This is how a textbook might be written but our guideline, Wikipedia:What Wikipedia is not explicitly says Wikipedia is not a textbook, and it is not our mission to teach a subject. In particular, headings should not be phrased as questions and "Magnetic Fields for Dummies" is definitely out. Our mission is to provide the facts, not teach the subject.

That's not to say the article should not be made more accessible to a general reader, that most definitely is our mission. I agree that opening with a definition section using vector notation is far from useful. It is not even correct—half the section is spent analysing the field of point charges before getting anywhere near an actual definition. The reader, if they even understand this, are going to run away with the idea that electric fields only exist around point charges. The electric field is the natural force that acts on electric charges, and the electric field strength is the force per unit charge acting on an arbitrarily small test charge n the field. It's as simple as that. There is no need to refer to Coulomb's law at all in the definition. All that analysis could come (much) later in the article. SpinningSpark 15:18, 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

Given an electric charge $q_{1}$ at position ${\boldsymbol {x}}_{1}$ in Euclidean 3-space, Coulomb's law states that a charge $q_{0}$ (with units of Coulombs) at position ${\boldsymbol {x}}_{0}$ experiences a force from $q_{1}$ with a magnitude that is directly proportional to both charges and inversely proportional to the square of the distance between them with a constant of proportionality, in a vacuum, equal to ${1 \over 4\pi \varepsilon _{0}}$, where ε₀ is the vacuum permittivity (also known as "the absolute permittivity of free space") with units C² m⁻² N⁻¹. This is written mathematically as...

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)

Removal of cat picture

The removed cat picture. The caption said: "Evidence of an electric field: styrofoam peanuts clinging to a cat's fur due to static electricity. The triboelectric effect causes an electrostatic charge to build up on the fur due to the cat's motions. The electric field of the charge causes polarization of the molecules of the styrofoam due to electrostatic induction, resulting in a slight attraction of the light plastic pieces to the charged fur. This effect is also the cause of static cling in clothes."

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)

I think your opinion that "The electric field... is not useful for laypersons and has no applicability to everyday-life." is, to put it charitably, a minority opinion. The example of "static cling" shown by the cat picture, an extremely common effect in everyday life, clearly refutes you, and there are many other examples, i.e. laser printers. Your arbitrary rule that "figures... that depict lines of electric flux are the only pictorial representation of the electric field that are relevant to the article." is way too restrictive. Scientific effects can be explained at different levels of complexity. In the cat picture, general readers don't have to understand dielectric polarization to get that the force of the electric field of the cat's fur is what holds the styrofoam on, and the caption explained that. My opinion is totally opposed to yours - I think electric fields are relevant in everyday life, but whether they are or not, it helps readers to see examples of them. --Chetvorno^TALK 17:05, 13 August 2020 (UTC)

The picture I (Chetvorno) replaced the cat picture with. The caption: "Effects of an electric field. The girl is touching an electrostatic generator, which charges her body with a high voltage. Her hair, which is charged with the same polarity, is repelled by the electric field of her head and stands out from her head."

That is very absurd. Do you know what a mathematical model is? The cat, and your new, ridiculously obnoxious picture of a girl, are just eye candy. They do not help explain the electric field at all, and I am not sure you know what it is. It is a mathematical model. As a mathematical model, nothing is added by showing obnoxious examples of everyday phenomena. Why not post a picture of a battery? Again, readers can find infinite applications of electric charges, their distributions, and currents in other articles more specific to those phenomena. In my opinion, much worse than adding no substance to the article, both of these pictures detract greatly from it. They absolutely kill the professionalism of the articles they are in, and after surfing around I don't think that is my opinion alone. I think everyone is encouraged to make articles more accessible to nontechnical readers, but I think that effort should be spent on providing better links and references so that core concepts can be learnt before moving on the more complicated concepts. These irrelevant pictures are distractions that lower the overall quality of the article. Edit. To underscore what I mean by all of this, both of these pictures can be explained to laypeople utilizing only electric potential energy, with no reference to the electric field at all. As the electric field is a mathematical model, other models can be used to solve lots of problems, especially common everyday-life problems.Footlessmouse (talk) 20:19, 13 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 found the cat picture fully appropriate, but the girl's picture even more so. In the latter the girl's hair even reflects the direction of the field lines. - DVdm (talk) 21:36, 13 August 2020 (UTC)

I do not think that makes it appropriate. I have started a discussion on the Physics Projects talk page, which will hopefully bring in some diverse opinions. Though I have to say, taking a picture of confetti falling from the ceiling is a perfect example of the gravitational field, each piece follows the gravitational field lines all the way to the ground. In addition, a picture of a sleeping baby in a crib is another example of "proof" of the gravitational field akin to these examples of the electric field. When used to try to explain something as common as gravity, though, it becomes very clear how obnoxious and irrelevant these phenomena are. — Preceding unsigned comment added by Footlessmouse (talk • contribs) 22:18, 13 August 2020 (UTC)

I tend to think of the pictures as being aimed at creating a "relatable first perception". This seems to be at odds with where the rest of the article is pitched. Without an explanatory section aimed at junior schoolers the picture of the girl seems a bit unconnected: those who relate to that might find even the lead too technical. I don't find the pictures particularly tasteful (I prefer illustrations that include fewer extraneous/unrelated factors, and I don't particularly hold with a pedagogical approach in an encyclopaedia), yet I don't see them specifically as inappropriate. The video captioned "Experiment illustrating electric field lines" I think is rather poor in all respects; if I were to choose between them, I would say that is more of a waste of bandwidth. —Quondum 23:26, 13 August 2020 (UTC)

I find that both the cat and the girl are appropriate. I guess I prefer the girl. The picture makes the article friendlier to people looking for a less than college level discussion. A little whimsy doesn't hurt anything. Constant314 (talk) 23:32, 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)

This is a good argument against my stance. My reservation is that the electric field is just a model, like the gravitational field. It does relate to the real world, but we don't talk about how the gravitational field is real, we talk about gravity being real, if anything. In the same way, I believe that these illustrations belong in other articles on electricity and electrical effects. The electric field is nothing more than the mathematical way we describe those, very real, very physical, effects. As such, I still believe this content is more appropriate in those other articles and that, if anything, we should do a better job of linking to them and explaining that.Footlessmouse (talk) 00:01, 14 August 2020 (UTC)

I'm sympathetic to the view that the electric field is just a model, but fundamentally that is true of everything in physics and most of what you perceive with your senses as well. Gravity isn't "real". There's no force pulling you toward the ground. What is real (as far as we know) is that mass bends space in such a way that your inertia causes you to move toward the center of mass. That too is a model of course, but we don't know what lies beyond that. Physics is a series of successively better models for the world around us. All of them are "wrong", in the sense that they are supplanted by better, more complex models. At every level, though, we must connect our models back to physical reality. The electric field is not more or less real than gravity. They are both models for the physical world. --Srleffler (talk) 04:10, 14 August 2020 (UTC)

I added the picture of the girl. I think both pictures are needed and appropriate. Wikipedia is a general encyclopedia. Readers who have never taken a science class will come to this page wanting the simplest possible explanation of what an "electric field" is. Both pictures are clearly of an electric field exerting force on a physical object. Nontechnical people can often comprehend abstract concepts better by seeing concrete everyday examples. --Chetvorno^TALK 23:52, 13 August 2020 (UTC)

I think the girl picture should be moved to the top of the article. Constant314 (talk) 00:01, 14 August 2020 (UTC)

• I'm more or less neutral on whether the images stay, but I do have to object to describing them as "obnoxious". You may argue over whether they are appropriate, but obnoxious? I also have to comment on the idea that readers who don't have a firm grasp of the mathematics should be pointed to other articles to understand the basics first. That says to me that you have not written a good encyclopaedia article. You might have an excellent textbook chapter, but that makes for a poor encyclopaedia page. Wikipedia is not a textbook (by policy). It should be more than a coffee table book, but not a textbook. Even readers who cannot grasp the mathematics should be able to get something out of it, and if a lightweight image helps with that, then why not. SpinningSpark 23:57, 13 August 2020 (UTC)

I find them obnoxious (it may be just me and one other guy on the electrostatics page, though) as they seem to be memes, eye candy that don't contribute anything. I fully agree the article can be written better, but finding the wording is very difficult. The cat picture removal was the first edit I made to this page and have only made marginal edits since, mostly adding links to math pages. I will keep trying to improve it where I can, outside of the pictures in question, but it is a slow process.Footlessmouse (talk) 00:06, 14 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)

[Arriving late] Both pictures are fun and illustrative. ~Kvng (talk) 14:59, 16 August 2020 (UTC)

New History section

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)

You're not proposing the History section as a replacement for pictures, are you? Or as a place to put the pictures? Just checking. --Chetvorno^TALK 02:11, 14 August 2020 (UTC)

That is up to the community, I am proposing a new history section that, at the very least, will contain the pictures, as I said above. Even if I were to write the proposed new section, I wouldn't make the pictures, and the first draft would just include what we have here, maybe with some offhand remark about electrostatic generators somewhere in the history to tie it in, making it much more appropriate. I would very much like to find better photos to go in the proposed history section, but I will not remove the photo of the girl from this, or any other, article unless there is some kind of consensus for it, if that is what you are really asking - I am fully aware that would be inappropriate.Footlessmouse (talk) 02:17, 14 August 2020 (UTC)

I know what you mean about memes and nonsensical eye candy pictures on technical sites, I've seen some horrible examples. But I really don't think these are in that class. And people do learn in different ways. --Chetvorno^TALK 02:57, 14 August 2020 (UTC)

I wouldn't mind, but I don't think it's a substitute for an introductory section that explains the subject in a nontechnical way without math, which readers have repeatedly been asking for. I think that should be at the top of the article. I know it's difficult to write, but we have to remember the elementary school kids, the high school dropouts, the single mothers training to be x-ray techs, and the Sociology majors who will be coming to this article. --Chetvorno^TALK 01:54, 14 August 2020 (UTC)

To a large extent, I agree with you here. We just have different approaches. I think the introduction, the parts above the definition section, is horribly written and a much better job can be done. I just can't find the words for it yet, I've been working on a draft for a couple of days, but it leaves a lot wanting. We need to do a much better job of linking to other articles that discuss the core concepts as well. Also, maybe something could be done to say something like "the electric field can either refer to the vector field which describes electrostatic phenomena or as a colloquial term for the effects and dynamics of electric charges", to disambiguate the concept a bit. But this, also, leaves a lot wanting.Footlessmouse (talk) 02:26, 14 August 2020 (UTC)

A history section could be useful. I encourage it. Constant314 (talk) 03:02, 14 August 2020 (UTC)

History sections should be compulsory on all science articles. SpinningSpark 11:48, 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)

Leads should not be written independently of the body of the article. They are meant to summarise the article contnt. You're not going to get that (necessarily) if you import the text from another article. Improvements to the body should come first, and then the lead can be reassessed. That's not to say the lead cannot be improved now, but it should be based on what is in the article now. SpinningSpark 08:22, 18 August 2020 (UTC)

Good point. I am thinking it might be helpful to have a short section for a nontechnical description that focuses on electric field lines emanating from charges, similar to the way they are described in the electricity article. History (mixed with applications) could follow. Also, the density of field lines (at each point) in illustrations of the electric field is (ideally), proportional to the electric field strength (at each point), which is never mentioned on either article, but may be helpful. Footlessmouse (talk) 09:59, 18 August 2020 (UTC)

I have come up with the following as the first sentance of a history section

The development of the electric field, and all of electrodynamics, as a quantitative subject happened over roughly a century: between Henry Cavendish's experiments in the early 1770s and James Clerk Maxwell's 1864 groundbreaking theory of a dynamical electromagnetic field and Heinrich Hertz's subsequent discovery of transverse electromagnetic waves.

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

Reverted edit 10/11/20

@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)

• Specifically the claim is that in an inhomogeneous material, permittivity can vary as a function of displacement. Footlessmouse (talk) 10:02, 11 October 2020 (UTC)

@Footlessmouse:, yes of course, in an inhomogeneous medium permittivity likely depends on location, but I think in an explicit formula we need a source for this functional dependency. If no author has ever done it, we surely can't do it either. I have been searching, but to no avail. Happy hunting! - DVdm (talk) 10:25, 11 October 2020 (UTC)

I also think that the edit was correct. It was simply making the mathematical formula agree with the text that came right before it. Constant314 (talk) 15:29, 11 October 2020 (UTC)

This is crazy! I've been looking through both CM and E&M textbooks and can't find anything! The closest I have come is Kittel, who shows the momentum-dependent Fourier transform of the permittivity without explicitly stating it's location dependence. It also, at one point, implies that permeability is location dependent. I am so sure that we learned about this at some point that I can't believe I can't find it. Footlessmouse (talk) 18:24, 11 October 2020 (UTC)

Welcome to the club - DVdm (talk) 18:28, 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:

${\text{curl }}\mathbf {H} =-i\epsilon \omega \mathbf {E} /c$

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)

Yes, looks good. The cite book template allows for an additional note to clarify the reason for writing $\epsilon (r)$. Go for it. - DVdm (talk) 19:44, 11 October 2020 (UTC)

I'm late to this party, but I think writing $\epsilon (r)$ 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 $\epsilon (r,E,\theta ,t)$ 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. SpinningSpark 11:58, 18 October 2020 (UTC)

@Spinningspark: The equation we are discussing is following a statement explicitly about inhomogeneous materials. Are you arguing we should delete that statement and the corresponding equation? Also, you can always say at each moment in time, but it is implicit. The reason it was hard to find an explicit quote is that physicists are hand-wavy and there is a lot of material to dig through to find an super niche point. Also, it is implicit that the r is a vector r, there was no discussion of requisite symmetries. We can bolden them, though. The electric field is a vector-valued function by definition, so the r must be a vector in the equation.Footlessmouse (talk) 12:21, 18 October 2020 (UTC)

Follow up, I made a mistake when adding the equation, it should be vector r. Also the tonsorial nature of non-isotropic mediums is briefly mentioned as a 3rd scenario under the inhomogeneous material. Footlessmouse (talk) 12:25, 18 October 2020 (UTC)

Section on applications of electric fields

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)

Proposed merge of Optical field into Electric field

"the electric field E is referred to as the optical field" fgnievinski (talk) 03:03, 13 May 2022 (UTC)

I think the optical field article should be deleted as being not notable. Constant314 (talk) 03:25, 13 May 2022 (UTC)

I agree, this seems to be a peculiarity of Hecht. Everybody else uses the term optical field in a vague hand-wavey way to mean the electromagnetic field generally. Hecht's textbook is widely used and if it had a radically different view of the subject it might be worth a mention. But I don't think it does - this is just Hecht's way of saying he is going to write the equations in terms of the E field rather than the H field. He is not saying that it is something entirely separate. I think the author of the article has misread him. SpinningSpark 07:56, 14 May 2022 (UTC)

Agree, delete. --Chetvorno^TALK 16:56, 4 June 2022 (UTC)

Chetvorno, it has already been redirected as a result of Wikipedia:Articles for deletion/Optical field. SpinningSpark 20:29, 4 June 2022 (UTC)