Conceptual Question about electric potential

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Discussion Overview

The discussion revolves around the question of whether a charged particle can move from a low electric potential to a high electric potential while experiencing a decrease in electric potential energy. Participants explore the relationship between electric potential and potential energy, particularly in the context of electrons and their behavior in electric fields.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that a charged particle cannot move to a higher potential and have a decrease in electric potential energy, arguing that a positive change in potential must correspond to an increase in potential energy.
  • Others propose that electrons, as negatively charged particles, can indeed move from a low electric potential to a high electric potential while their potential energy decreases, suggesting that this occurs as their potential energy is converted into kinetic energy.
  • A participant challenges the assertion that no work is done on the electron, stating that work is performed by the electric field, leading to a decrease in potential energy and an increase in kinetic energy.
  • There is a discussion about the work-energy theorem and conservation of energy, with references to the relationships between work, kinetic energy, and potential energy.
  • Some participants clarify that the behavior of negatively charged particles differs from that of positively charged ones, emphasizing the importance of the charge's sign in determining the direction of energy changes.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between electric potential and potential energy, particularly concerning the behavior of electrons. There is no consensus on whether a charged particle can move from low to high potential while decreasing potential energy, as multiple competing perspectives are presented.

Contextual Notes

The discussion highlights the complexity of electric potential and potential energy, with participants referencing various principles such as the work-energy theorem and the effects of charge sign. Some assumptions about the nature of work done and the definitions of potential energy are not fully resolved.

Herjap
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Guys, i really need help on answering this question...

Can a charged particle ever move from a low electric potential to a high electric potential and yet have its electric potential energy decrease? Explain.

What i think is that, no it is not possible for a charged particle to move to a higher potential and yet have its electric potential energy decrease. This is so because any particle which experiences a positive change in potential cannot have a decrease in electric potential energy.
 
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Electric potential V is related to potential energy U according to U = QV, where Q is the charge. Can you increase V while decreasing U? If so, what is the condition?
 
Herjap said:
Guys, i really need help on answering this question...

Can a charged particle ever move from a low electric potential to a high electric potential and yet have its electric potential energy decrease? Explain.

What i think is that, no it is not possible for a charged particle to move to a higher potential and yet have its electric potential energy decrease. This is so because any particle which experiences a positive change in potential cannot have a decrease in electric potential energy.
As far as i am concern electron is a particle which moves from a low electric potential to a high electric potential and yet have its electric potential energy decrease.As it moves naturally from lower to higher potential (no work is done on it, so no increase in potential energy) it's potential energy is converted into kinetic energy as it moves.
 
gracy said:
As far as i am concern electron is a particle which moves from a low electric potential to a high electric potential and yet have its electric potential energy decrease.As it moves naturally from lower to higher potential (no work is done on it, so no increase in potential energy) it's potential energy is converted into kinetic energy as it moves.
This is not true. If it moves due to the field, there is work done (by the force exerted by the field) and the potential energy decreases.
The work done by the field is equal to the negative of the change in potential energy. It is also equal to the change in kinetic energy.
You can think either in terms of work and KE:
W=ΔKE (work-energy theorem)

or in terms of KE and PE, replacing W by -ΔPE
-̶Δ̶P̶E̶=̶-̶Δ̶K̶E̶ ̶o̶r̶ ̶
-ΔPE=ΔKE or
ΔPE+ΔKE=0 (conservation of energy)

The first "picture" (work and KE) is more general. The last one works only for conservative forces, when you can derive the force from a potential.
 
Last edited:
nasu said:
-ΔPE=-ΔKE or
is it right?
 
As far as i am concern electron is a particle which moves from a low electric potential to a high electric potential and yet have its electric potential energy decrease.Am i right till here?
 
gracy said:
is it right?
No, I corrected. Just using copy-paste without paying enough attention. :)

And I think your last statement is correct. Negative particles move from low to high potential. From negative to positive.
 
nasu said:
And I think your last statement is correct. Negative particles move from low to high potential. From negative to positive.
and it's (negative particle for eg.electron) potential energy decreases when it moves from lower to higher potential,right?
 
Last edited:
Herjap said:
Guys, i really need help on answering this question...

Can a charged particle ever move from a low electric potential to a high electric potential and yet have its electric potential energy decrease? Explain.

What i think is that, no it is not possible for a charged particle to move to a higher potential and yet have its electric potential energy decrease. This is so because any particle which experiences a positive change in potential cannot have a decrease in electric potential energy.
answer to your question would be electron is a particle which can move from a low electric potential to a high electric potential and yet have its electric potential energy decrease.
 
  • #10
Electrical Potential is defined in terms of Work done on a Unit Positive Charge (1C), brought from infinity. The Potential Energy of a charge (positive or negative) at a certain position will be relative to some other position and will depend upon its sign and, when it moves to increase or decrease its position in the Potential Field, the sign of the change in its Potential Energy will also be affected by the sign of its charge. This is pretty obvious really if you think of needing to put energy In when you move 'uphill' and getting energy out when you move 'downhill' ; whether it's uphill or downhill (electrostatically speaking) will depend upon the sign of the test charge.
So, when you are dealing with electrons (-) things will be the other way round from the situation with a unit positive charge.
 

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