Potential vs. Potential energy

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Discussion Overview

The discussion revolves around the concepts of electric potential and potential energy, particularly focusing on the relationship between electric fields and potential, as well as the distinction between potential and potential energy. The scope includes theoretical explanations and conceptual clarifications related to electrostatics.

Discussion Character

  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions why the electric field is defined as the negative divergence of potential, suggesting a need for clarification on this convention.
  • Another participant explains that moving to lower potential energy corresponds to losing energy, which implies that the electric field points towards lower potential, necessitating the negative derivative of potential.
  • A participant seeks clarification on the phrase "go down in potential energy," asking if it refers to moving closer to the charge creating the electric field.
  • It is noted that if the charge creating the electric field is negative, moving closer would indeed lower the potential energy; otherwise, it would not.
  • Another participant states that if work is done when moving from point A to point B, then point B is at a lower potential than point A, emphasizing the convention used in these discussions.
  • There is a clarification that potential energy is defined as the potential multiplied by the charge of the object, distinguishing it from potential itself.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between potential and potential energy, with some clarifying distinctions while others seek to understand the implications of potential changes. The discussion remains unresolved regarding the conceptual nuances of these terms.

Contextual Notes

There are limitations in the discussion regarding the definitions of potential and potential energy, as well as the assumptions underlying the conventions used in electrostatics. Some mathematical steps and their implications are not fully explored.

Shan K
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I was reading electrostatic and found out that the electric field is just the negetive divergence of potential . My questions are why are we taking the negetive divergence ? Electric field is a conservative field and so it can be written as divergence of a scaler function but why we ar taking the negetive one instead of positive . And is this potential and potential energy are same ?
 
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If you go down in potential energy, you lose energy. Therefore, the force should point towards points of lower potential. The direction of electric field is the force for positive charges (convention), therefore you have to take the negative derivative of the potential to get the electric field.
The potential energy depends on the charge of the object.
 
mfb said:
If you go down in potential energy, you lose energy. Therefore, the force should point towards points of lower potential. The direction of electric field is the force for positive charges (convention), therefore you have to take the negative derivative of the potential to get the electric field.
The potential energy depends on the charge of the object.

what do u mean by 'go down in the potential energy ' is it going nearer to the object who is responsible for the electric field ?
 
If that object has a negative charge, yes, otherwise no.

"down" -> lower potential (=lower potential energy with positive charges)
 
If you 'get work out' when you move from A to B, then B is at a lower potential than A. If you have to put work in, B is a higher potential. That's the convention that's used and always applies. It avoids any confusion for situations of attraction and repulsion.
 
So are u saying that potential and potential energy are same ?
 
No, potential energy is the potential multiplied by the charge of your object.
 
O. Thats great . Thanks
 

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