it produces its own magnetic field the magnetic field cannot be turned on and off - it is there all the time Bar magnets and horseshoe magnets are examples of permanent magnets. The iron filings ...

it produces its own magnetic field the magnetic field cannot be turned on and off - it is there all the time Bar magnets and horseshoe magnets are examples of permanent magnets. An iron rod placed ...

Elon Musk says China wants assurances that the rare-earth magnets needed to build Optimus won't be used for "military ...