Overview
Like other areas of Physics, Electromagnetism was found to conserve energy.Work
The derivation of the amount of energy in an electromagnetic field is derived from a an understanding of the amount of work required to assemble the charges and current that generates the field.- Work Associated with Charge
the amount of work required to assemble a set of charges is given by
{% \frac{\epsilon_0}{2} \int E^2 dV %}
- Work Associated with Current
the amount of work required to assemble a set of currents is
{% \frac{1}{2 \mu_0} \int B^2 dV %}
Energy
The energy per unit volume is then given by
{% W = \frac{1}{2} (\epsilon_0 E^2 + \frac{1}{\mu_0} B^2) %}