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

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1. Feb 9, 2017

Iftekhar Uddin

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.)

2. Feb 9, 2017

Staff: Mentor

No; where E = 0 the change in electric potential = 0. (ΔV = 0)

3. Feb 9, 2017

Iftekhar Uddin

Then does that apply to just V as well? And thanks for the quick response! :)

4. Feb 9, 2017

Staff: Mentor

If I understand you correctly, no.

5. Feb 9, 2017

Staff: Mentor

That second equation describes the potential at some distance from a positive charge. (It assumes V = 0 when infinitely far from the charge.)

6. Feb 9, 2017

Iftekhar Uddin

7. Feb 10, 2017

Chandra Prayaga

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.