Wikipedia electric charge page confusion

Click For Summary

Discussion Overview

The discussion centers around the representation of electric charge and electric field lines on Wikipedia's page about electrical charge. Participants explore the implications of the visual depiction of electric field lines, the conventions used in illustrating these concepts, and the relationship between electric fields and the forces experienced by charged objects.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the depiction of electric field lines in relation to the flow of electrons, suggesting that the image may be showing conventional current.
  • Another participant clarifies that the lines represent electric field lines and are not indicative of electron current, emphasizing their role in drawing equipotential surfaces.
  • Some participants note that electric field lines conventionally point from positive to negative charges, but this is a convention rather than a physical emission of fields from charges.
  • There is a discussion about the representation of electric field strength, with denser lines indicating stronger fields.
  • One participant suggests that arrows could be represented in both directions on the lines for better representation, while another argues that a single arrow is preferable for simplicity.
  • A later reply explains that positive and negative charges experience opposite forces in an electric field, with the direction of arrows indicating the force on a positive charge.
  • Another participant confirms that the electric field direction is defined by the force on a positive probe charge, noting that it could have been defined differently but was not.

Areas of Agreement / Disagreement

Participants generally agree on the convention of electric field lines pointing from positive to negative charges and the implications of this for understanding forces on charges. However, there are differing opinions on the best way to represent these lines visually, and the discussion remains unresolved regarding the optimal depiction of electric field lines.

Contextual Notes

Some assumptions about the conventions of electric field representation and the nature of electric fields are not explicitly stated, leading to potential misunderstandings. The discussion does not resolve the nuances of these representations.

Cash Fulton
Messages
24
Reaction score
1
Why does Wikipedia's page on electrical charge have a picture of a positivity charged object with arrows going to a negatively charged object? Doesn’t electrons flow from a negatively charged object to a positively charged object? Or is the picture just showing conventional current?

220px-VFPt_charges_plus_minus_thumb.svg.png

Thanks.
 
Physics news on Phys.org
Those lines are just the electric field lines, it has nothing to do with electron current. The significance of drawing electric field lines comes out, for example if one wants to draw equipotential surfaces, which is a surface on which every electric field line must pierce through perpendicularly.
 
  • Like
Likes   Reactions: Cash Fulton
blue_leaf77 said:
Those lines are just the electric field lines, it has nothing to do with electron current. The significance of drawing electric field lines comes out, for example if one wants to draw equipotential surfaces, which is a surface on which every electric field line must pierce through perpendicularly.
So an electric field goes from positive to negative?
 
Giving an arrow to the electric field lines is just a convention, it's not like the positive charge acts as an electric field emitter and the negative charge as the receiver. Electric field lines can also indicate the electric field strength dependence on position, the denser the lines the stronger the field there. In your picture, we can infer that the electric field strength is stronger around either charges and gets weaker as one goes farther from both of them.
 
  • Like
Likes   Reactions: Cash Fulton
blue_leaf77 said:
Giving an arrow to the electric field lines is just a convention, it's not like the positive charge acts as an electric field emitter and the negative charge as the receiver. Electric field lines can also indicate the electric field strength dependence on position, the denser the lines the stronger the field there. In your picture, we can infer that the electric field strength is stronger around either charges and gets weaker as one goes farther from both of them.
Ah, so you could say that it would be a better representation to put arrows going in both directions on those lines.
 
Cash Fulton said:
Ah, so you could say that it would be a better representation to put arrows going in both directions on those lines.
No matter how you look at it, assigning one arrow (either direction) to each line is better than two arrows of opposite directions because this way you don't always need to draw the charge type on all existing charges in the system.
 
  • Like
Likes   Reactions: Cash Fulton
blue_leaf77 said:
No matter how you look at it, assigning one arrow (either direction) to each line is better than two arrows of opposite directions because this way you don't always need to draw the charge type on all existing charges in the system.
Appreciate you helping dude.
 
No. Positive and negative charges will experience opposite forces from any given electric field. The arrows give us a way of visualizing this. A positive charge will feel a force in the direction of the arrows while a negative charge will feel a force in the direction opposite that of the arrows. So in your picture the positive charge is pulled towards the negative charge, which is with the arrows, while the negative charge is pulled towards the positive charge, or against the arrows. Both end up meeting in the middle, assuming they were free to move.
 
  • Like
Likes   Reactions: Cash Fulton and vanhees71
Cash Fulton said:
So an electric field goes from positive to negative?
Yes!
 
  • Like
Likes   Reactions: Cash Fulton
  • #10
The direction of the electric field at any point is (by definition) the direction of the force experienced by a small, positive probe charge placed in the field at the given point.
It could have been defined based on a negative probe but it just wasn't.
 
  • Like
Likes   Reactions: Cash Fulton

Similar threads

  • · Replies 3 ·
Replies
3
Views
713
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 58 ·
2
Replies
58
Views
5K