Electromagnetic Field

Now let us consider the field from two charges, one positive and one negative, a distance d apart. We call this combination of charges a dipole. Remember, opposite charges attract, so this is not an unusual situation. A hydrogen atom, for example, consisting of an electron (negative charge) and a proton (positive charge) is a very small dipole, as these particles do not sit right on top of each other. According to the superposition principle mentioned above, we can just add the fields from each individual charge and get a rather complicated field. If we only consider the field at a position very far from the dipole, we can simplify the field equation so that the field is proportional to the product of the charge value and the separation of the two charges. There is also dependence on the distance along the dipole axis as well as radial distance from the axis.