Electric Potential Energy Concept

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Discussion Overview

The discussion revolves around the concept of electric potential energy, specifically addressing the nature of electric potential, the assignment of reference points, and the relationship between work and potential energy in the context of electric fields. The scope includes theoretical considerations and conceptual clarifications.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that electric potential is a scalar quantity, noting the absence of direction associated with potential energy.
  • The same participant expresses uncertainty about the ability to assign a value of zero to electric potential at the origin, suggesting that potential depends on a reference point.
  • Another participant questions the relationship between the change in potential energy and the path taken, referencing the equation U = qV and its dependence on distance.
  • There is a claim that the work required to move a charge from potential Vi to Vf is given by q(Vf - Vi), with one participant suggesting this is incorrect due to the relationship between work and potential energy.
  • One participant confirms that q(Vf - Vi) is correct for work done against the electric force, while noting that if considering work done by the electric field, it would be q(Vi - Vf).
  • Another participant agrees with the correctness of the earlier points but expresses uncertainty specifically about the second point regarding reference potentials.
  • A later reply clarifies that the second point is true if the potentials of all charges are offset with respect to a chosen ground reference.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the assignment of zero potential and the implications of reference points. While some points are affirmed, there remains disagreement and lack of consensus on the implications of these concepts.

Contextual Notes

There are limitations regarding the assumptions made about reference points and the conditions under which the relationships between work and potential energy hold true. The discussion does not resolve these uncertainties.

Who May Find This Useful

This discussion may be useful for students and individuals interested in understanding the nuances of electric potential energy, particularly in theoretical and conceptual contexts.

r0306
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I'm unsure if the following is true or not in the absence of external forces:
  • Electric potential is a scalar quantity.
This I know is true because there is no direction associated with potential energy.
  • It is always possible to assign a value of zero to the electric potential at the origin.
This I am completely unsure of though I think it is true because potential depends on a reference point that you can set yourself.
  • The change in a particle's potential energy depends on the total length of its path between two points.
I suspect that this is true because U = qV and V is dependent on the distance between the points.
  • The work required to move a charge q from a point at potential Vi to a point at potential Vf is q(Vf - Vi).
This should be false because (delta)U = q(Vf - Vi) and W = -(delta)U so it should be -q(Vf - Vi) instead.

Can someone please verify my reasoning and correct me if I'm wrong? Thank you.
 
Physics news on Phys.org
q(Vf - Vi) is correct for the work done by the force opposing the electric force. If the work done by electric field was being considered, it would be q(Vi - Vf).
 
TESL@ said:
q(Vf - Vi) is correct for the work done by the force opposing the electric force. If the work done by electric field was being considered, it would be q(Vi - Vf).
That means all of the points listed are true then? I'm really uncertain about the second point.
 
Your second point is true as long as you offset the potentials of all the charges in the system wrt. the ground you take.
 
what did u end up getting for this?
 

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