Probably a Dumb Question: How are E and (delta)V correlated?

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Discussion Overview

The discussion revolves around the relationship between electric field (E) and electric potential (V), specifically exploring the equations ΔV = Ed and V = kq/r. Participants are trying to clarify how changes in the electric field relate to changes in electric potential, particularly in cases where E equals zero.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant states that if E = 0, then electric potential must also be 0, expressing confusion about the relationship between the two concepts.
  • Another participant corrects this by asserting that when E = 0, the change in electric potential (ΔV) is 0, but does not necessarily imply that the electric potential (V) itself is 0.
  • A subsequent participant questions whether this reasoning applies to the electric potential (V) itself, receiving clarification that it does not.
  • Discussion includes the context of the second equation, V = kq/r, which describes the potential due to a point charge and assumes V = 0 at an infinite distance from the charge.
  • One participant emphasizes that the equations ΔV = Ed and V = kq/r apply to different situations, noting that ΔV = Ed is valid only for uniform electric fields.
  • Another participant introduces the relationship E = -∇V, indicating that E is a vector quantity, which adds complexity to the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the implications of E = 0 for electric potential, with some asserting that it leads to ΔV = 0 while others clarify that this does not mean V itself is zero. The discussion remains unresolved regarding the implications of these relationships.

Contextual Notes

Participants highlight limitations in understanding the conditions under which the equations apply, particularly regarding uniform versus non-uniform electric fields and the assumptions tied to the potential of point charges.

Iftekhar Uddin
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What I Think I Understand: ΔV = Ed (d being dstance) and that V = kq/r

please correct me if I'm misunderstanding those.

What I need to know: When E = 0, what happens to the electric potential? and vice versa.

Me Working it out: So if i use the first equation up here, If E = 0, then electric Potential = 0. Even with the second equation wouldn't I compare the net electric field with the net potential at a point? If so, then my answer remains the same. Either my equations are wrong or I'm really misunderstanding a simple concept. I may just be reaching my burnout point with physics right now. (I'm a few days in of focused physics studying and I can't wrap my head around simple concepts like this anymore.)
 
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Iftekhar Uddin said:
So if i use the first equation up here, If E = 0, then electric Potential = 0.
No; where E = 0 the change in electric potential = 0. (ΔV = 0)
 
Doc Al said:
No; where E = 0 the change in electric potential = 0. (ΔV = 0)

Then does that apply to just V as well? And thanks for the quick response! :)
 
Iftekhar Uddin said:
Then does that apply to just V as well?
If I understand you correctly, no.
 
Iftekhar Uddin said:
Even with the second equation wouldn't I compare the net electric field with the net potential at a point?
That second equation describes the potential at some distance from a positive charge. (It assumes V = 0 when infinitely far from the charge.)
 
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Iftekhar Uddin said:
What I Think I Understand: ΔV = Ed (d being dstance) and that V = kq/r

please correct me if I'm misunderstanding those.

What I need to know: When E = 0, what happens to the electric potential? and vice versa.

Me Working it out: So if i use the first equation up here, If E = 0, then electric Potential = 0. Even with the second equation wouldn't I compare the net electric field with the net potential at a point? If so, then my answer remains the same. Either my equations are wrong or I'm really misunderstanding a simple concept. I may just be reaching my burnout point with physics right now. (I'm a few days in of focused physics studying and I can't wrap my head around simple concepts like this anymore.)
The two equations that you gave are valid for two separate situations. ΔV = Ed is valid if the electric field is uniform. If it is not, then the relation is approximately valid only for short distances, and along a direction parallel to the field.
The second equation, V = kq/r gives the potential of a point charge q at the origin. In this case, the electric field is not uniform, so your first equation ΔV = Ed is not correct.
In all cases, the relation between electrostatic field and potential is: E = - ∇V. I typed E in bold to state that E is a vector.
 

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