The charge densities in Eqs. (3.1) through (3.3) may be uniform or nonuniform over the dimensions given. A uniform charge density means that the charge distributed over any equal section of surface, line, or volume is the same; that is, it is independent of the variables. A nonuniform charge density occurs when the charge in different sections of the charge distribution depends on location. Note, also, that the charge densities given above as examples are rather large densities.