Electromagnetism: electric charge, fields, current and magnetism. From Coulomb’s and Ohm’s laws to electromagnetic induction and circuits — how charges and fields actually work.
Electromagnetism is the physics of electric charge and magnetism, and of the fields that carry the force between them. It runs from the current in a wire to the light leaving a star, because visible light is itself an electromagnetic wave.
| Relationship | Equation | What it tells you |
|---|---|---|
| Coulomb's law | F = k·q1·q2 / r² | Force between two point charges |
| Ohm's law | V = I·R | Voltage, current and resistance in a conductor |
| Electric field | E = k·Q / r² | Field strength around a point charge |
| Faraday's law | ε = −N · ΔΦ/Δt | EMF induced by a changing magnetic flux |
| Magnetic force | F = q·v·B·sinθ | Force on a charge moving through a field |
| Electrical power | P = V·I | Power delivered by a circuit |
