Electricity & Magnetism
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EM Energy Density

Energy stored per unit volume in EM fields.

Formula

u=12ε0E2+B22μ0u = \tfrac{1}{2}\varepsilon_0 E^2 + \frac{B^2}{2\mu_0}

Variables

EElectric field
BMagnetic field

Did You Know?

Empty space carrying an electromagnetic field actually stores energy, which is how sunlight ferries power across the void.

energy densityem field