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Maxwell's equations
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Four equations unifying electricity, magnetism and light.
Four equations: Gauss's law for E, Gauss's law for B (no monopoles), Faraday's law and Ampère–Maxwell law. With the Lorentz force they describe all classical electromagnetism and predict light at c = 1/√(μ₀ε₀).
A massive unification in 1865.
Foundation of relativity.
In more detail
Maxwell's four equations describe electric and magnetic fields and their sources: Gauss's law for electricity, Gauss's law for magnetism, Faraday's law, and Ampère's law with displacement current. Together they predict electromagnetic waves.
Real-world uses
- Maxwell's equations underpin all of electrical engineering and optics.
- Radio, radar, wireless communication and light all follow from these equations.
- Physicists use Maxwell's equations to predict radio waves, explain light and design antennas and optical devices.
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Frequently asked questions
Are there four equations?
Yes, usually written as four differential or integral equations.
What do they predict?
Electromagnetic waves travelling at the speed of light.
Why are Maxwell's equations important?
They unify electricity, magnetism and light, and predicted that electromagnetic waves travel at the speed of light.
Related topics in Magnetism & Induction
Back emf in a motor · LR circuit growth and decay · Maxwell's displacement current · Magnetic monopoles · Vector potential · Magnetic levitation