Generating Electromagnetic Waves

AI Thread Summary
Electromagnetic waves are generated by charged particles accelerating, creating changes in electric and magnetic fields as described by Maxwell's equations. A permanent magnet generates its magnetic field through the spin of electrons, but moving the magnet does not typically produce electromagnetic waves efficiently. The discussion highlights that while a permanent magnet can influence electromagnetic fields, it is primarily electric charges that are the source of electromagnetic waves. The example of a pulsar is noted, where waves are produced due to electrons being accelerated by a strong magnetic field. Overall, the conversation emphasizes the role of electric charges in generating electromagnetic waves, even when considering the effects of permanent magnets.
Caio Ferrari
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Every book I ever read describes a electromagnetic wave as a phenomena generated by charged particles accelerating. This will produce a change in electric field that induces a magnetic field.
But, due to Maxwell equations a change in magnetic field will also produce an electric field. So, if a hold a permanent magnet bar into an spring mass system, does it will produce an electromagnetic wave?
 
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How does the permanent magnet generate its magnetic field? With charged electrons and their spin.
How do you change the magnetic field? By accelerating the object with its charges ;).

Moving a permanent magnet up and down should produce electromagnetic waves, probably with a terrible efficiency.
 
So, even a magnetic field is generated by a charged particles accelerated. That's ok.
It means that the only source of electromagnetic waves is a electric charge.

But I've never seen a book or even a example in which a wave is produced by a permanent magnet. Even a pulsar produces its waves because the electrons are being accelerated by a very strong magnetic field.
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
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