Places electric potential is zero when 2 charges

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Homework Help Overview

The discussion revolves around understanding the conditions under which the electric potential is zero in the presence of two charges. Participants are exploring the locations where the electric potential cancels out, specifically questioning the reasoning behind zero potential at designated points in different regions.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are attempting to visualize and understand why the electric potential is zero at specific points, questioning the influence of each charge on those points. There is a focus on calculating voltages from each charge and considering their contributions to the total potential.

Discussion Status

The discussion is active, with participants raising questions about the reasoning behind the zero potential locations and the implications of charge positions. Some guidance has been offered regarding the calculation of potentials and the nature of their summation, but there remains a lack of consensus on the conceptual understanding of the phenomenon.

Contextual Notes

Participants are grappling with the implications of charge placement and the resulting electric potential in different regions, noting that the regions are defined arbitrarily. There is an acknowledgment that both charges influence the potential throughout the space, even beyond their immediate vicinity.

JustStudying
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Homework Statement



elecquestion.jpg


i'm having a bit of trouble understanding/visualising why the electric potential is zero in the red cross within region III and the green dot within region II

from my current understanding, the green dot is where the potentials from both charges are equal and opposite therefore cancel out (am I right?), but I have no idea why the electric potential is zero at the red cross

can anyone help me out?

Homework Equations


V = kq/r


The Attempt at a Solution

 
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Calculate the voltages separately for each of the two charges, for each of the positions along the line. Note that the voltages decrease as the point is further away.

Then see which ones add up to zero at the same point.

Note that if the two charges were equal, then the zero point would be midway between them.
 
The total Electric potential due to these two charges at the red cross must be summed as scalars. So write down the potentials as a sum to find the total potentials that's it.
 
I was hoping if anyone could explain why there are TWO points where the potential is zero i.e I simply don't get why the potential is zero at the red cross - the 3q charge is not even in region III so how could it cause a zero potential there?, the actual number crunching isn't too difficult.
 
Generate a plot. Vary the positions and charges.

Remember that the potential goes off in both directions, as far as you can go.
 
JustStudying said:
I was hoping if anyone could explain why there are TWO points where the potential is zero i.e I simply don't get why the potential is zero at the red cross - the 3q charge is not even in region III so how could it cause a zero potential there?, the actual number crunching isn't too difficult.
The regions are arbitrary definitions on your line. Both charges influence the potential everywhere.

If you extend the analysis to two dimensions, you get a full circle of points with zero potential.[/size]

Please do not open multiple threads for the same topic, I deleted the other one.
 
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