Consider a time varying magnetic field. This induces an electric field upto infinity as per Faraday law and other related laws.

Is energy stored in this induced electric field?

If so, what kind of energy is it since it is said to not have a potential associated with it?

Further is it something like this - The source provides energy separately for both inducing the field and changing the magnetic field?


1 Answer 1


Yes, electromagnetic energy is stored in both E and B fields. The EM energy density is $U=\frac{E^2+B^2}{8\pi}$ in Gaussian units. Integrating U gives the energy.

  • $\begingroup$ Thank you for the correction. $\endgroup$ Commented Aug 31, 2020 at 3:10

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