Comparing 100J and -100J of Electric Potential Energy

Click For Summary

Discussion Overview

The discussion revolves around the comparison of 100 J and -100 J of electric potential energy, exploring the implications of their magnitudes and signs in the context of electric potential energy configurations. The scope includes theoretical interpretations and practical considerations of electric potential energy in physics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants argue that while 100 J and -100 J have the same magnitude, the sign indicates the nature of work done when bringing a +1C charge to those potentials.
  • One participant interprets the question as comparing two configurations of the same system, noting that one configuration has 200 J less electrical potential energy than the other.
  • Another participant suggests that the question could be theoretical or practical, indicating a need for clarification from the original poster regarding their intent.
  • There is a mention that the question might lack semantic clarity, raising doubts about its formulation.

Areas of Agreement / Disagreement

Participants express differing interpretations of the question and its implications, indicating that multiple competing views remain without a clear consensus on the nature of the comparison.

Contextual Notes

Participants note the need for additional context from the original poster to better understand the intent behind the question, highlighting potential ambiguities in its phrasing.

rpthomps
Messages
182
Reaction score
19
Is the 100 J of electric potential energy actually greater than -100 J of electric potential energy?
 
Physics news on Phys.org
They have the same magnitude but the sign is the indication of the work done (energy needed) to bring a +1C of charge from an infinite distance to points with those two potentials. The definition is that Positive work is needed to bring +1C to the +110J point (pushing up a hill) but negative work is done (i.e. energy is got out) then the +1C is brought to the -100J point (sliding down to a valley).
 
rpthomps said:
Is the 100 J of electric potential energy actually greater than -100 J of electric potential energy?
Given the way the question is phrased and the units that are used, I would interpret it to be about the potential energy of two configurations of the same system. One with a potential energy 100 J more than an arbitrary reference potential and one with 100 J less than the arbitrary reference.

Clearly, one has 200 J less electrical potential energy than the other.
 
  • Like
Likes   Reactions: russ_watters and sophiecentaur
jbriggs444 said:
Given the way the question is phrased and the units that are used, I would interpret it to be about the potential energy of two configurations of the same system. One with a potential energy 100 J more than an arbitrary reference potential and one with 100 J less than the arbitrary reference.
Clearly, one has 200 J less electrical potential energy than the other.
Sounds fair and I can't find fault with that. The question could either require a totally theoretical answer or something practical. We would need the OP to give us a bit of help with the context. What does he actually want to know and why?
Can @rpthomps help us to help him more, please?
 
  • Like
Likes   Reactions: jbriggs444
sophiecentaur said:
The question could either require a totally theoretical answer or something practical.
Or it might have the syntax of a question but be devoid of semantics.
 
Thanks guys for the response! The question, was answered, as intended by @sophiecentaur but @jbriggs444 brought up another way of thinking about it.
 

Similar threads

High School E. Potential Energy: Uniformly Charged Hollow Sphere and Point Charge
  • · Replies 4 ·
Replies
4
Views
2K
High School Some Questions about Electric Current/Capacitors to help my understanding
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Electric Potential in circuit
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Work done by electric field of an irregularly shaped conductor
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad What effects does an electric field have on potential energy?
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Electric Potential -- Is my understanding correct?
  • · Replies 6 ·
Replies
6
Views
1K
Undergrad How is Potential Difference Created across a Resistor?
  • · Replies 21 ·
Replies
21
Views
4K
Undergrad Electric Potential vs Electric Potential Energy
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Potential Energy of an Electric Dipole in a Uniform Field
  • · Replies 11 ·
Replies
11
Views
4K
Undergrad What's the electric potential of the Earth?
  • · Replies 13 ·
Replies
13
Views
3K