Speed of Electric Field: Is it the Speed of Light?

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SUMMARY

The speed of electric fields is indeed the speed of light in a vacuum, denoted as 'c'. Changes in electric and magnetic fields propagate at this speed, confirming that while fields themselves are not physical entities, their effects and changes can be observed traveling at light speed. The discussion clarifies that when using retarded times, the apparent influence of the field is due to the motion of charges, which causes changes in the field that propagate at 'c'.

PREREQUISITES
  • Understanding of electromagnetic fields and their properties
  • Familiarity with the concept of speed of light (c)
  • Knowledge of retarded time in electromagnetic theory
  • Basic principles of charge movement and field interactions
NEXT STEPS
  • Research the concept of retarded time in electromagnetic theory
  • Study Maxwell's equations and their implications for field propagation
  • Explore the relationship between electric fields and electromagnetic radiation
  • Investigate the physical interpretation of fields in classical electromagnetism
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Physicists, electrical engineers, students of electromagnetism, and anyone interested in the propagation of electric and magnetic fields.

BeauGeste
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"speed of field"?

Is it correct to say that a field (i.e. electric) travels at the speed of light?
We've been taught that only electromagnetic radiation in a vacuum travels so can we say that the effect of E travels at c also?
I always thought this to be the case but someone argued that fields are not physical and are 'just there'. Can anyone elaborate please?
 
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It is better to say that changes in a field propagate at some speed. For electric and magnetic fields in a vacuum, that speed is c.
 
ok that makes sense now.
I was a little confused because when using retarded times, it appears that the potential or field 'influences' at c but it's really because when using retarded times, a charge is moving and therefore the field is changing (and the change propagates at c).
thanks.
 

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