Electromagnetic mass of an electron

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Discussion Overview

The discussion revolves around the concept of electromagnetic mass of an electron, specifically addressing questions about electrostatic energy, the definition of electromagnetic mass, and the interpretation of symbols used in related formulas. The scope includes theoretical and conceptual clarifications.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the meaning of "electrostatic energy ##E_{em}##" and whether it refers to electric potential energy, noting that such energy typically exists between two charges.
  • Another participant suggests that "##m_{em}##" is the electromagnetic mass of the electron at rest and raises the issue of what constitutes non-electromagnetic mass, implying it may be "0" based on the formula presented.
  • There is a query regarding the symbol "c" in the context of the electron being at rest, with one participant asserting that "c" represents the speed of light.
  • A response clarifies that ##E_{em}## is related to the energy required to assemble a sphere of one electron charge, which is necessary for calculating mass.
  • Another participant points out that there are no strict rules for subscripts in scientific notation, suggesting that the author's choice may not always align with common conventions.

Areas of Agreement / Disagreement

The discussion contains multiple competing views and interpretations, particularly regarding the definitions and implications of electromagnetic mass and the meaning of specific terms and symbols. No consensus has been reached.

Contextual Notes

Participants express uncertainty about the definitions and implications of terms like "electrostatic energy" and the notation used in formulas, indicating a reliance on the author's choices without established conventions.

PainterGuy
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Hi,

I was reading the following Wikipedia article and couldn't make sense of few points. I'd appreciate it if you could help me with it.

1599699951272.png

Source: https://en.wikipedia.org/wiki/Electromagnetic_mass#Rest_mass_and_energy

Question 1:
What is this "electrostatic energy ##E_{em}##"? Is it some kind of electric potential energy? But electrostatic potential energy exists between two charges.

Question 2:
I think "##m_{em}##" is electromagnetic mass of electron at rest. What would be non-electromagnetic mass electron? From the formula it looks like non-electromagnetic mass of electron would be "0".

Question 3:
I don't think the letter "c" in the stands for the speed of light since electron is at rest. It is not stated what "c" is. Could you please comment on it?

Thank you!
 
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I direct you to the article about classical electron radius before waving my hands rapidly at your questions.

answer1: ##E_{em}## represents the required to assemble a sphere of magnitude one electron charge (thereby overcoming the repulsion). The size of the sphere is chosen to give correct number for the mass.

answer2: from answer1 it is chosen so that ##m_{em}= E_{em}/c^2##

answer3: c is light speed

The complete answers here in fact contain ##\hbar## and are therefore quantum mechanical in nature particularly for complete description of the electromagnetic field.
 
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Thank you!

1599720224520.png


If it's electrostatic energy then shouldn't the subscript be "es" in "##E_{em}##"?
 
There are no general rules regarding subscripts. Author decides what he/she wants to use. It does not have to make sense for everyone.
 

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