Suppose we take an empty universe. This universe contains only a proton and a proton spinning in circles of small radius – basically an electric charge and a magnet respectively. We will also call them that.
We now move the load. It also generates a magnetic field and should repel or attract the magnet. How do we explain this attraction or repulsion if we say that the magnet moves relative to the charge? In this respect, does this magnet generate an electric field (because it moves) that attracts or repels the charge?
Answer
The electric and magnetic fields that you observe in a certain coordinate system are indeed relative to that coordinate system. In another coordinate system, which moves relative to the first, you notice different electric and magnetic fields. A certain force can clearly manifest itself in a coordinate system as a magnetic force, in another coordinate system it ‘appears’ to be an electrical force! (as you indicate in your example). That is why one speaks of the electromagnetic interaction: those two things cannot really be separated. The correct way to transform electric and magnetic field vectors to another coordinate system is through the Lorentz transformation formulas.
Answered by
Professor Walter Lauriks
Physics Acoustics
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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