In electromagnetic waves, the energy is equally shared between the electric and magnetic fields. The electric energy density is given by $u_E=\frac{1}{2}\epsilon E^2$ and the magnetic energy density is $u_B=\frac{1}{2}\frac{B^2}{\mu }$. For a wave propagating in a vacuum or non-conducting medium, these two densities are equal at every point.

Final Answer: Electric energy density is equal to the magnetic energy density