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2 results for “fields”

Formulae (2)

EM Energy Density

u = \tfrac{1}{2}\varepsilon_0 E^2 + \frac{B^2}{2\mu_0}

Energy stored per unit volume in EM fields.

Electricity & MagnetismAdvanced

Maxwell's Equations

\begin{aligned}\nabla\cdot\mathbf{E}&=\tfrac{\rho}{\varepsilon_0} & \nabla\times\mathbf{E}&=-\tfrac{\partial\mathbf{B}}{\partial t}\\ \nabla\cdot\mathbf{B}&=0 & \nabla\times\mathbf{B}&=\mu_0\mathbf{J}+\mu_0\varepsilon_0\tfrac{\partial\mathbf{E}}{\partial t}\end{aligned}

The four equations that describe how electric and magnetic fields are generated by charges and currents, and how they interact — the complete classical theory of electromagnetism.