Can magnetic field exist without electric field?

In summary, the book claims that a permanent magnet can have an electric field even if there is no electric field present. This is not a practical fact as there are no magnets without electric fields.
  • #36
Thierry said:
What about transformer cores? the magnetic field oscillates at 50 hz but there's no electric field in a metal. There's eddy currents but no electric field, or am I missing something?
Yes there certainly are eddy currents in the core metal. But why would you conclude that there is 0 electric field? Core metal is conductive with value ##\sigma##, eddy current density has value ##J##, and remembering Ohm's law in 3 dimensions: ##J=\sigma E##, so that ##E=J/\sigma##.

Does that help? Best regards.

Claude
 
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  • #37
Thierry said:
there's no electric field in a metal

...under electrostatic conditions.
 
  • #38
cabraham said:
Yes there certainly are eddy currents in the core metal. But why would you conclude that there is 0 electric field? Core metal is conductive with value ##\sigma##, eddy current density has value ##J##, and remembering Ohm's law in 3 dimensions: ##J=\sigma E##, so that ##E=J/\sigma##.

Does that help? Best regards.

Claude
ah yes, it does. Thanks!
 
  • #39
jtbell said:
...under electrostatic conditions.
I see. of course, thanks!
 

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