What happens to the Electrical Potential the closer we are to a point charge?

AI Thread Summary
The electrical potential of a point charge approaches infinity as one gets closer to the charge, which raises questions about the implications for another charge approaching it. This behavior indicates that as a second charge nears a positive charge, the force between them becomes increasingly difficult to overcome. The mathematical model of Coulomb's law, which describes the force between point charges, fails when the distance approaches zero, as it cannot account for physical limitations like the finite size of the charges. Therefore, while the potential mathematically trends towards infinity, real-world physics introduces constraints that prevent charges from reaching that state. Understanding these limitations is crucial for accurately interpreting electric potential in practical scenarios.
SebastianRM
Messages
39
Reaction score
4
So I have been wondering:
The potential for a point charge at the origin, is described as:
(Using the reference point at infinity): V=1/(4πε) * q/r
My question is, what happens to this Potential the closer we are to the point charge, and so the closer we would get, the Potential seems to go towards infinity, which does not make sense, so I would like to understand how to approach the idea since my approach gives me an illogical answer.
 
Last edited by a moderator:
Physics news on Phys.org
Yes, it does go toward infinity, as you suspected. So what does this mean for another charge as it approaches the one at the origin?
 
Its potential would be stronger the closer this one is to it? And how can a Potential go towards infinity, I feel pretty lost on the subject. Thank you for the help btw!
 
So let's agree that you cannot put zero in the denominator. Physically, the distance between two charges will always be some tiny amount.
If the charge at the origin is positive, bringing another positive charge close to it will become increasingly difficult, as you get closer. Maybe this site will help you. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/potpoi.html
 
  • Like
Likes SebastianRM
SebastianRM said:
the Potential seems to go towards infinity, which does not make sense,
Indeed it does not. This is the math telling you that ##F=CQ_1Q_2/r^2## for point particles only works when ##r\ne{0}##.

If f you try to bring two charged objects together to drive the potential and the force between them to infinity, some other physics that you've been ignoring for larger values of ##r## will start to matter and Coulomb's law is no longer the whole story. For example, if the objects have non-zero sizes ##R_1## and ##R_2##, you can't reduce the distance between them to less than ##R_1+R_2## so plugging a smaller value into Coulomb's law makes no sense.
 
  • Like
Likes SebastianRM and scottdave
I was using the Smith chart to determine the input impedance of a transmission line that has a reflection from the load. One can do this if one knows the characteristic impedance Zo, the degree of mismatch of the load ZL and the length of the transmission line in wavelengths. However, my question is: Consider the input impedance of a wave which appears back at the source after reflection from the load and has traveled for some fraction of a wavelength. The impedance of this wave as it...
Back
Top