Time varying magnetic field in conductors

[Thierry]

Hi
Something is bugging me a little. According to Maxwell's equations the magnetic and electric fields are decoupled in the static case, so that magnetic fields can exist in metals but not electric fields. For time varying fields, though, both fields are linked so that one cannot exist without inducing the other. That's why EM waves don't penetrate much in metals. So how come there can be strong oscillating magnetic fields in transformer cores? What's happening to the accompanying electric field?
Cheers

 

[Vailanor]

The electric field accompanying the strong oscillating magnetic field in a transformer core is very small and is cancelled out by the electrical insulation between the primary and secondary coils. This is why electromagnetic waves do not penetrate much in metals. The oscillating magnetic field in the transformer core is the result of the alternating current flowing through the primary coil, which induces a magnetic field in the core that interacts with the secondary coil, inducing an alternating current in it.