Talk:Electric field

Coulomb's law equation

The equation of Coulomb's law in this page differs from the one in the Coulomb's law page under the vector form section, first paragraphs, in that here the Euclidean norm of the vectorial distance is not taken before squaring it. I also think the notation in the Coulomb's law page is better in that the unit vector is written as the unit vector of the vectorial distance, while here different letters are used for the positions and the unit vector which makes them seem unrelated. Using the same notation for a certain equation across all wikipedia pages seems the way to go to me; it results in more clarity. I'd like some opinions about this as I dislike making changes without a consensus. TheGoatOfSparta (talk) 12:28, 30 June 2023 (UTC)

I agree with you. The vector equations in this article are incorrect because $x_{2}-x_{1}$ is a vector and ${(x_{2}-x_{1})}^{2}$ is ambiguous at best. All the instances in this article need to be fixed. Mixing x with r also adds needless complexity. I do not have a preference between x or r but I do prefer $r_{21}$ over $r_{2,1}$. Constant314 (talk) 13:46, 30 June 2023 (UTC)

I need a good lesson on formatting (which I can't take now) before I even begin to change anything on wikipedia. So if you know how to make the changes it is faster if you do it. TheGoatOfSparta (talk) 13:50, 30 June 2023 (UTC)

I'll wait a little longer to see if anyone else has an opinion. As for learning formatting, just go to your sandbox and experiment. Constant314 (talk) 17:57, 30 June 2023 (UTC)

Got it, it's just I won't have time these days (exams) TheGoatOfSparta (talk) 17:57, 30 June 2023 (UTC)

I agree it is better not to change letters. I prefer the removal of the coma as well (I also like when vectors have some kind of arrow symbol as a ideal formal documentation style) Bill field pulse (talk) 21:55, 10 January 2024 (UTC)

I guess I should have indicated that those changes have been completed. We don't generally put arrows above vectors. The reliable sources have gotten away from that. This article uses bold for vectors. Constant314 (talk) 01:20, 11 January 2024 (UTC)

That's what I thought. Even though the arrows are clearer, when lots of vectors are being noted the arrows and comas are extra work. If readers familiarize with the latest conventions they should understand.

Should we ask ourselves "Is the goal to help less knowledgeable readers keep up (clarity) or to advance the subject matter (easy writing style)?" Clarity would be my pick despite my being a lazy writer, and a novice here. Bill field pulse (talk) 19:51, 11 January 2024 (UTC)

Here are some examples:

$$\mathbf {F} =q\mathbf {E} +q\mathbf {v} \times \mathbf {B}$$

$${\overrightarrow {F}}=q{\overrightarrow {E}}+q{\overrightarrow {v}}\times {\overrightarrow {B}}$$

$${\overrightarrow {\mathbf {F} }}=q{\overrightarrow {\mathbf {E} }}+q{\overrightarrow {\mathbf {v} }}\times {\overrightarrow {\mathbf {B} }}$$

I would oppose arrows for the following reasons:

• Conformance with other technical articles.
• Vectors and matrices are often intermixed.
• None of the examples in the math manual of style (MOS:MATH) use arrows, although they are not forbidden.
• Possible rendering problems on small screens.

The manual style emphasizes that symbols should be defined. I think that would take care of any confusion. Constant314 (talk) 20:30, 11 January 2024 (UTC)

You are absolutely right the bold face is clear and obvious. The arrows are messy. A well chosen clearly bold face like that is better for all. Thank you for your attention to this. It is much appreciated and helps my understanding. Bill field pulse (talk) 20:50, 11 January 2024 (UTC)

Static electric field

"In the special case of a steady state (stationary charges and currents)" This text is under mathematical formulation->electrostatics. I feel like "stationary charges" can be elaborated on. The charges can move, but their position relative to a non accelerating frame of reference has to be constant for the equation in that section to work (please correct me if I am wrong). So if, for example, a charge has the same constant velocity as its frame of reference the equation works. TheGoatOfSparta (talk) 13:47, 6 July 2023 (UTC)

Forget for a moment that charge comes in discrete particles. Just think of as continuous stuff. In a DC circuit with continuous charge, the charge distribution doesn't change from moment to moment. Think of as when charge moves, some identical charge seamlessly takes its place. So, as long as the distribution of charge and current density is constant, you can assume static conditions. Constant314 (talk) 15:14, 6 July 2023 (UTC)

I don't think the situation you describe is electrostatic. "When movement takes place, Einstein's theory of relativity must be taken into consideration, and a result, an extra factor is introduced, which alters the force produced on the two objects. This extra part of the force is called the magnetic force, and is described by magnetic fields" taken from Wikipedia. TheGoatOfSparta (talk) 15:18, 6 July 2023 (UTC)

Yes, those are static magnetic fields. If you have two wires carrying DC current, then there is a force between them. Remember, in statics, nothing is moving, except classically, we make an exception for charge so long as ${\frac {d\rho }{dt}}=0$ and ${\frac {dJ}{dt}}=0$. If there is a force between wires, then there must be something restraining the wires for it to be a static case.

Also remember that Maxwell's equations are consistent with special relativity, as they are written, in all inertial frames of reference. That sort of led the way to the discovery of special relativity. Constant314 (talk) 15:42, 6 July 2023 (UTC)

I will just trust you because I lack knowledge from here on. TheGoatOfSparta (talk) 15:45, 6 July 2023 (UTC)

In a static charged body the hidden motion of electrons only need be random or balanced to cause a net zero magnetic field. As long as the motions are not aligned to cause a magnetic field there will be no measurable magnetic field. A Permanent magnet has some such aligned charge motion within the atoms. Bill field pulse (talk) 22:25, 10 January 2024 (UTC)

I think Constant314 is saying that as long as the current is steady and the forces have stabilized over time we have reached a static condition. Bill field pulse (talk) 22:39, 10 January 2024 (UTC)

Electric field difinition issue

I make difinition of electric field more technical, according to you less technical difinition is preferred because it is easy to understand, you are correct but in long run and in case of understanding theory soo deeply these less technical difinition bring a lot of confusion . Let's clearify it with a example, according to your preferred definition(less technical difinition) electric field is a physical field which surround an electrically charged particle ,here reader can be confuse that electric field only surround particle and it will take some time for them to understand that it surround any electric charge no matter if it a particle or not most of learner take a lot of time to understand it and that time can be save if we use word electric charge insted of electrically charge particle.

CONCLUSION — LESS TECHNICAL DEFINITIONS ARE EASY TO UNDERSTAND BUT MAKE THINGS CONFUSING AND DIFFICULT TO UNDERSTAND IF WE WANT TO UNDERSTAND IN DEPTH. AryanpateI (talk) 17:54, 9 August 2023 (UTC)

All electric charge exists in the form of charged particles. “Charge density” which appears in Maxwell’s equations is an approximation which breaks down at small scales.

At even smaller (atomic) scales, the Uncertainty Principle makes a particle’s charge smear out, appearing as an actual space charge density. This is the origin of atomic and molecular orbitals. However if the charge of a portion of space is measured, it is always found to be quantized, concentrated at one or more points as particles.

I think it is good for general readers to understand that charge comes in the form of particles, so I support use of the term “charged particles”

--Chetvorno^TALK 16:37, 11 August 2023 (UTC)

I agree. Charge is a property of some particles and not abstract stuff. I do not oppose having a couple of sentences explaining that in classical E&M that charge may be treated as continuous abstract stuff. Constant314 (talk) 17:39, 11 August 2023 (UTC)

I would like to see the best mix of good math and good language both as attempts to explain the underlying reality. I like including something like "the the electric field is a part of the physical change to space that occurs due to the presence of a charge. Charges are field creators. When a charge arrives at a point in space time. This field starts at the charge, positive or negative, and moves out from the charges in all directions." Bill field pulse (talk) 23:12, 10 January 2024 (UTC)

Electric field intensity

we have to make a heading of electric field intensity. There is a lot of confusion between electric field and electric field intensity between people.

If we observe we find out that the unit of electric field given is actually unit of electric field intensity. AryanpateI (talk) 15:47, 11 August 2023 (UTC)

The “electric field intensity” at a point is just the magnitude of the electric field vector. I don’t see that this requires a separate heading --Chetvorno^TALK 16:53, 11 August 2023 (UTC)

I agree, but I am not be against having a sentence or two about electric field intensity. By the way, I haven't seen any confusion between electric field and electric field intensity, although I do not doubt that it happens sometimes. In most cases it is not necessary to distinguish between the two terms as they both refer to the same physical phenomenon. Constant314 (talk) 17:34, 11 August 2023 (UTC)

Given that "electric field" is the force for an infinitesimal charge, and "electric field intensity" is just the same force per unit test charge, I think this would warrant at most a single sentence. I personally don't think it's important enough to add it, myself, but if someone else wants to, here's a reference. (Jackson doesn't seem to mention the term at all, adding to my skepticism of its necessity.) PianoDan (talk) 17:47, 11 August 2023 (UTC) PianoDan (talk) 17:47, 11 August 2023 (UTC)

@PianoDan, huh? I'd think that field intensity i. e. field strength is just the magnitude of the filed, a scalar. Field != force, not even dimensionally. And the force on a 0+ charge is pretty much 0. Also, what's the point of saying "electric field strength" = "strength of the electric field", that explains nothing 68.199.122.141 (talk) 18:20, 11 August 2023 (UTC)

Yeah, I could have been clearer, because I misread the reference I was looking at.

I should have said electric field IS the force *per unit charge* on an infinitesimal test charge. I thought L&L were drawing a distinction between consideration of the field of the test charge itself, but they aren't.

That said - L&L, who are the ONLY reference on my shelf to even use the term "electric field intensity", use it as a vector. Jackson and Griffiths don't seem to use it at all. So given that the only reference I can find uses the term interchangeably with the article definition of electric field, I'm going to say we definitely shouldn't include this without sourcing that indicates it's WP:DUE. PianoDan (talk) 20:49, 11 August 2023 (UTC)

Harrington, uses the terms electric intensity for the E field. Kraus uses electric field intensity. Hayt uses electric field intensity. Straton uses electric field intensity. Constant314 (talk) 03:16, 12 August 2023 (UTC)

If we observe we will find out that electric field is actually a physical quantity which change with space and time because electric field is a physical quantity it have dimension which is same as force and charge also a physical quantity,by dividing a physical quantity by another we will get physical quantity. If compare dimension of electric field and electric field intensity they both are different (dimension) .If two physical quantity are same their dimension should have to be same ,but in this case it is different,then how we can say that electric field and electric field intensity both are same .I agree that they both can use interchangeably but it don't men bot are same .

DIMENSIONS OF ELECTRIC FIELD —

[MLT^-2]

DIMENSION OF ELECTRIC FIELD INTENSITY —

[MLT^-1A]

Do observe difinition of electric field everything will clear. AryanpateI (talk) 08:50, 12 August 2023 (UTC)

Both of those are wrong. The dimensions of the electric field are not the same as force. It is force divided by charge. Constant314 (talk) 11:24, 12 August 2023 (UTC)

Constant314, check again dimension of electric field intensity don't you think it is correct AryanpateI (talk) 15:04, 12 August 2023 (UTC)

The units are wrong. Electric field and electric field intensity have the same units, which you can find in the info box of this article. Constant314 (talk) 19:10, 12 August 2023 (UTC)

Aryan, cite your sources or this discussion is over. What you're saying is wrong on many levels. This very article will tell you what the dimension of E is, and it's different from yours. Electric field is E , electric field strength is |E|, and that's all. 68.199.122.141 (talk) 11:25, 12 August 2023 (UTC)

Thanks you all due to this a lot of concept cleared .I will update if It required. Hey 68.199.122.141 |E| is actually magnitude of electric field (don't have direction) not strength of electric field AryanpateI (talk) 15:02, 12 August 2023 (UTC)

Magnitude and strength are used interchangeably when discussing the electric field. Constant314 (talk) 19:11, 12 August 2023 (UTC)

References