Does Electric Field & Magnetic Field need a medium to travel?

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"green" wrote in message
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"Sanny" wrote in message
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Earth Magnetic Field is present in Air. So Magnetic Field do not need
any medium to travel.

is present in vaccuum too., also in conductors, and rocks

Are you saying there's no such thing as a perfect vacuum, or that
magnetism can still travel in a perfect vacuum? Both or neither?


yes to all, after all it is a field.

the field is modified by paramagnetic or diamagnetic materials, but you knew
that.