Classical electromagnetic theory

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Discussion Overview

The discussion revolves around classical electromagnetic theory, particularly focusing on the concepts of acceleration, radiation of energy by charged particles, and the implications of the Rutherford and Bohr models. Participants explore the definitions and conditions of acceleration in the context of classical electrodynamics and challenge each other's interpretations.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that classical electromagnetic theory requires a particle to not only change direction but also increase speed to be considered accelerating.
  • Others argue that a change in direction constitutes acceleration, even if speed remains constant, particularly in uniform circular motion.
  • A participant questions the validity of the assertion that acceleration necessitates an increase in speed, suggesting a misunderstanding of classical electrodynamics.
  • There is a claim that Maxwell stated that an accelerating charged particle radiates energy, but some participants challenge the accuracy of this attribution, suggesting it may have been made by others like J.J. Thomson or J.J. Larmor.
  • One participant discusses the limitations of the Rutherford model, proposing that Maxwell's interpretation of acceleration does not align with their understanding of classical electrodynamics.
  • Another participant introduces Bohr's model, suggesting it offers a different perspective on energy radiation and acceleration, but this point is met with skepticism regarding its relevance to the original question.
  • Several participants express frustration over repeated claims about acceleration and speed, indicating a lack of consensus on the interpretation of classical electrodynamics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions and implications of acceleration in classical electromagnetic theory. Multiple competing views remain regarding the relationship between acceleration, speed, and energy radiation.

Contextual Notes

There are unresolved issues regarding the definitions of acceleration and the conditions under which charged particles radiate energy. Participants reference various models and theorists, leading to potential misunderstandings and misattributions.

Vaibhav Dixit 1008
According to classical electromagnetic theory,for acceleration a particle must not only change its direction but it should also increase its speed. But Maxwell said that a particle accelerates then it radiates energy.(this is with reference to Rutherford model). But actually the particle is not accelerating because it is changing its direction not speed. So is classical theory wrong or Maxwell didn't get classical theory or Rutherford a genious..??
 
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Vaibhav Dixit 1008 said:
But actually the particle is not accelerating because it is changing its direction not speed.
A change in direction is an acceleration too.
 
But according to classical electrodynamics
If a particle is to accelerate then it should not only change its direction but speed must also change.
 
Vaibhav Dixit 1008 said:
but speed must also change.

No. You can have acceleration and constant speed at the same time.
 
I know that we can have acceleration and constant speed at same time.
But according to classical electrodynamics a particle must also change its speed in order to accelerate during uniform circular motion.
 
Vaibhav Dixit 1008 said:
But according to classical electrodynamics a particle must also change its speed in order to accelerate during uniform circular motion.
Then how is that circular motion uniform?
 
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Vaibhav Dixit 1008 said:
But according to classical electrodynamics
If a particle is to accelerate then it should not only change its direction but speed must also change.
Can you cite your source for this? I think you may just be misunderstanding some other point that is being made
 
Vaibhav Dixit 1008 said:
According to classical electromagnetic theory,for acceleration a particle must not only change its direction but it should also increase its speed. But Maxwell said that a particle accelerates then it radiates energy.(this is with reference to Rutherford model). But actually the particle is not accelerating because it is changing its direction not speed. So is classical theory wrong or Maxwell didn't get classical theory or Rutherford a genious..??
Did Maxwell actually say that? I thought it was JJ Thompson and JJ Larmor a few years later.
 
Not helpful.
 
  • #10
Let me make it more theoretical
When we talk about limitations of Rutherford model, Maxwell quoted that an accelerating charged particle radiates energy and its energy continuously decreases and it comes to rest. But this term acceleration doesn't fit here.
According to law of classical electrodynamics if a charged particle is to accelerate then it must increase its speed. There is a clause here that the speed of particle should neither be constant nor be decreasing. It should increase. So I think Maxwell said wrong thing.
 
  • #11
Now I come to another point. Bohr was really clever. He said that particle doesn't radiate energy. How can that be possible??
See what Bohr actually did. He did a clever usse of law of electrodynamics. According to Bohr a particle can move from low energy level to high energy level. In doing so it doesn't radiate energy because magnitude of velocity decreases which is in coordination with law. Now after 10 raised to power -8 seconds it returns back. Now speed of particle increases. It radiates energy. That's what I want to say.
Now tell Maxwell was not a good student.
 
  • #12
Vaibhav Dixit 1008 said:
According to law of classical electrodynamics if a charged particle is to accelerate then it must increase its speed.

We keep telling you this is wrong and you keep saying this. Why is that?
 
  • #13
Vaibhav Dixit 1008 said:
That's what I want to say.
Now tell Maxwell was not a good student.

You mixed so many different things... Bohr model has nothing to do with your question, because it's not classical. And you seem to ignore what people write to you...
 
  • #14
Vaibhav Dixit 1008 said:
if a charged particle is to accelerate then it must increase its speed.
Vaibhav Dixit 1008 said:
He said that particle doesn't radiate energy
Please send me a PM with your sources for these.
 

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