This particular thought crossed my mind while deriving the expression for energy density of electric field in parallel plate capacitor.
Energy density= $\frac12 \epsilon E^2$
It appears to me that initially when the plates were touching, the interface atoms were neutral.When we slowly pull the plates apart, electrons get separated from the interface atoms creating negative charge on one plate and positive on the other.
The work done in separating the plates is stored as the energy of the field of the capacitor.If we take one plate to infinity,we get electric field due to a single charged plane surface and the work done in taking the plate to infinity is stored as the energy of this field.
Anyways my questions are :-
Consider a single atom in place of the capacitor.Let us apply a force on the electron to separate it from the nucleus.Let us take this electron to infinity slowly.We are left with a positive nucleus.Will the work done in taking the electron to infinity be stored as the electric field of the positive nucleus?
In case any of my assumptions or arguments is incorrect,please provide proper rectification.