What charges generate EM waves in free space?

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SUMMARY

The discussion centers on the generation of electromagnetic (EM) waves in free space, emphasizing that electric and magnetic fields are produced by oscillating charges, as described by Maxwell's equations. It is established that while photons do not carry charge, they can interact with charged particles, such as electrons, which facilitate the propagation of these fields. The conversation also highlights Jefimenko's equations as a means to understand how these fields propagate through a vacuum after being generated by charges. Additionally, the mechanism of sunlight as a source of EM waves is identified as primarily due to black body radiation.

PREREQUISITES
  • Understanding of Maxwell's equations
  • Familiarity with Jefimenko's equations
  • Basic knowledge of electromagnetic theory
  • Concept of black body radiation
NEXT STEPS
  • Study Maxwell's equations in detail
  • Research Jefimenko's equations and their implications
  • Explore the concept of black body radiation and its applications
  • Investigate the interaction between photons and electrons in electromagnetic wave generation
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Physicists, electrical engineers, students of electromagnetism, and anyone interested in the principles of electromagnetic wave propagation and generation.

Kaushik Classes
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as we know light travel in vacuum because of oscillation of electric and magnetic field and both are perpendicular to each other. But i don understand how these electric and magnetic fields get generated in vacuum. as electric filed can vary by oscillating charge and that generate varying electric filed causing varying magnetic field. So what are these charge that travel with light to keep generating electric and magnetic field.
 
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There is no charge traveling with the photon.

When a photon is adsorbed it can move an electron. The electron has a charge.
 
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stefan r said:
There is no charge traveling with the photon.

When a photon is adsorbed it can move an electron. The electron has a charge.
but how these electric field get generated?could you please explain this concept?
 
Kaushik Classes said:
but how these electric field get generated?could you please explain this concept?
A changing magnetic field will create an electric field and vice versa; this is described by Maxwell's equations. Thus, if you can accelerate a charge in a way that starts the electrical and magnetic fields changing, the change will continue to propagate.

If you google for "Maxwell's equation wave" you'll find the detailed derivation.
 
Kaushik Classes said:
But i don understand how these electric and magnetic fields get generated in vacuum.
I wouldn’t say that they get generated in vacuum. They get generated by charges, and then they propagate through vacuum. This is described by Jefimenko’s equations

https://en.m.wikipedia.org/wiki/Jefimenko's_equations
 
Dale said:
I wouldn’t say that they get generated in vacuum. They get generated by charges, and then they propagate through vacuum. This is described by Jefimenko’s equations

https://en.m.wikipedia.org/wiki/Jefimenko's_equations
Agree with you . as once they are generated electric and magnetic field sustain each other and they progress.
so how does the sun light travel and what is the mechanism that generate the electromagnetic wave from sun?
 
Kaushik Classes said:
Agree with you . as once they are generated electric and magnetic field sustain each other and they progress.
But first of all, an electric field can exist in a vacuum somehow. And so can magnetism.
 

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