Electric Potential vs Electric Potential Energy

Click For Summary

Discussion Overview

The discussion revolves around the concepts of electric potential and electric potential energy, particularly in the context of a problem involving an electron moving in an external electric field. Participants explore the relationship between changes in electric potential energy and electric potential, seeking to clarify the conceptual understanding of these terms.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant expresses confusion about how the electric potential energy can decrease while the electron moves to a higher potential, despite understanding the mathematical calculations involved.
  • Another participant notes that since the electron has a negative charge, the change in potential energy will always have the opposite sign of the change in potential.
  • A follow-up question is raised about whether a positive charge would result in the change in potential energy having the same sign as the change in potential.
  • Participants confirm that if the charge were positive, the change in potential energy would indeed have the same sign as the change in potential.

Areas of Agreement / Disagreement

Participants generally agree on the relationship between the signs of potential energy and potential for positive and negative charges, but the conceptual understanding of how energy loss corresponds to a higher potential remains a point of confusion for at least one participant.

Contextual Notes

The discussion highlights the dependence on the definitions of electric potential and electric potential energy, as well as the implications of charge sign on these concepts. There are unresolved conceptual challenges regarding the interpretation of energy changes in relation to potential changes.

Who May Find This Useful

Readers interested in the conceptual foundations of electric potential and electric potential energy, particularly in the context of charged particles in electric fields, may find this discussion relevant.

Alex Hughes
Messages
54
Reaction score
13
So in my physics textbook a problem is stated. We are given an external electric field directed downwards of 150N/C. We are then told that an electron is released in the electric field and it moves upwards 520m. Finally we are asked to calculate the change in electric potential energy of the released electron and through what potential change does it move. I understand the math behind the problem, the amount of work = -(change in electric potential energy). Since work is (force * distance) and in an electric field the force is (q*E), to find the change in electric potential energy it becomes -(qEdcos(theta)). They find the answer and the change in electric potential energy of the electron is said to have DECREASED by a certain amount. Then to find the change in electric potential, they divide by the charge of the electron and say the electric force does work to move the electron to a HIGHER potential. That's where I'm confused. How can the electric potential energy decrease, but move to a higher potential. Am i not understanding the definition of each term? Please somebody help, I'm so confused. Thanks.
 
Physics news on Phys.org
And like I said, I understand the math behind it, I'm just trying to understand it conceptually. Obviously the potential is higher because the electric potential energy is negative and you divide by the charge of an electron which is also negative, giving you a positive value. But conceptually it doesn't make sense to me that a LOSS in energy results in a HIGHER potential.
 
Since the charge is negative the change in potential energy will always have the opposite sign of the change in potential.
 
Dale said:
Since the charge is negative the change in potential energy will always have the opposite sign of the change in potential.
So, if the charge was positive, the change in potential energy would have the same sign as the change in potential?
 
  • Like
Likes   Reactions: Dale
Alex Hughes said:
So, if the charge was positive, the change in potential energy would have the same sign as the change in potential?
Yes, exactly
 

Similar threads

Undergrad Electric Potential in circuit
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Confused about work done on charge
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Electric Potential -- Is my understanding correct?
  • · Replies 6 ·
Replies
6
Views
1K
Undergrad What effects does an electric field have on potential energy?
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Work done by electric field of an irregularly shaped conductor
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How a Battery creates a Potential difference in an electrical current
  • · Replies 14 ·
Replies
14
Views
6K
Undergrad When Electric Field is 0 is potential also 0?
  • · Replies 3 ·
Replies
3
Views
6K
Graduate Potential Energy of an Electric Dipole in a Uniform Field
  • · Replies 11 ·
Replies
11
Views
4K
Undergrad Uniform Electrical potential energy
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Video: 'How electricity actually works'
  • · Replies 30 ·
2
Replies
30
Views
4K