(c) Dr Paul Kinsler. [Acknowledgements & Feedback]
This is part of an information maze -- see the index-file for the full picture.
The theory of electro-magnetic-fields unifies electric-fields and magnetic-fields. That the two are closely related is obvious from a simple thought experiment.
Imagine you are a stationary charged object (e.g. a proton) which produces an electric-field. You see a moving electron, being attracted by your electric-field. This moving electron produces both an electric-field (which attracts you) and a magnetic-field, which doesn't affect you (because you are stationary).
Now ask the electron what they see. They say they are stationary, and producing an electric-field; and it is you who are moving and producing a magnetic-field! Who is right?
In order to be consistent, we know that both descriptions are correct, and that electric-fields and magnetic-fields are parts of the same thing; and they are described more correctly as electro-magnetic-fields. The theory of electro-magnetic-fields allows you to easily change your frame-of-reference, and work out which electric-fields and magnetic-fields will be seen for a given situation and particular frame-of-reference,
Large charges make electro-magnetic-fields which can accelerate charged particles (e.g. electrons) to high energies. Moving electric charges cause varying electro-magnetic-fields, and charges that oscillate create electro-magnetic-waves. These electro-magnetic-fields are described by Maxwells-equations. If you apply quantum-mechanics to Maxwells-equations, you get quantum-electro-dynamics, which provides a description of photons.
The electro-magnetic-field is one of the fundamental forces. The others are the weak-force, the strong-force, and gravity.
XINDEX: weak-force, vector, strong-force, proton, polariton, photon, magnetic-field, magnetic-charge, light, gravity, force, electro-magnetic-waves, electric-field, electric-charge, index-file.
XKEYWORD: electro-magnetic-field
20010720 20000205 19981021 (c) Paul Kinsler
Email Feedback: Dr.Paul.Kinsler@physics.org
LOGBUG