Relating electric constants to the speed of light ?

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Discussion Overview

The discussion revolves around the relationship between electric constants (permittivity and permeability) and the speed of light, as derived from Maxwell's equations. Participants explore the implications of this relationship, particularly in the context of relativity and experimental observations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant presents the equation 1/sqrt(EP) = c, linking the permittivity and permeability constants to the speed of light and suggesting a deeper conceptual exploration related to relativity.
  • Another participant notes that the values of vacuum permeability and permittivity were determined through experiments that initially seemed unrelated to light, raising questions about how these constants might change under different conditions, such as high speeds.
  • A subsequent reply discusses the perception of magnetic fields when charged particles are in motion relative to an observer, indicating that different observers may measure different magnetic fields due to relative motion.
  • Another participant elaborates on Maxwell's equations, explaining how the inclusion of displacement current led to the derivation of wave equations for electromagnetic fields, which predict that the speed of these waves in a vacuum is c, linking this to the foundations of special relativity.

Areas of Agreement / Disagreement

The discussion includes multiple competing views and remains unresolved, particularly regarding the implications of the electric constants and their relationship to the speed of light under varying conditions.

Contextual Notes

Participants express uncertainty about how the electric and magnetic constants might behave in different experimental setups, particularly at relativistic speeds, and the implications of these changes for the understanding of electromagnetic theory and relativity.

Who May Find This Useful

This discussion may be of interest to those studying electromagnetism, special relativity, or the historical development of physics concepts related to light and electromagnetic theory.

cragar
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1/sqrt(EP)=c
where E= Permittivity constant
P= permeability constant .
My teacher wanted us to think about this result that Maxwell got
and how it would lead to problems and eventually lead to relativity
can some one give me a hint what he is getting at this is not a home work problem he just wanted us to think about it .
 
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Well... hopefully you know that the vacuum permeability and permittivity (the electric and magnetic constants) were determined by experiments which, at the time, seemed to be completely unrelated to light. I'm talking about measuring the tiny forces between charged pith balls and electric wires with current flowing through them, that sort of thing. Then they calculated [itex]1/\sqrt{\epsilon_0 \mu_0}[/itex] and found that it was equal to the speed of light.

Now think about this: what if you took all those experiments on some futuristic spaceship, fired it up to half the speed of light, and did the experiments again? What would happen to the value of the electric and magnetic constants?
 
thanks for the response , so like if I have charged particles and I am moving
to someone on the ground the particles are moving so we would perceive different magnetic fields .
 
Maxwell's addition of the displacement current that completed his equations also allowed him to derive wave equations for the electric and magnetic fields. The speed of these wave equations were found to be c. So Maxwell's equations not only predict electromagnetic waves, they also stipulate that their speed in vacuum is c.

This is the starting point for deriving special relativity.
 

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