Given only an uniform electric field with unit vectors in the x, y, and z directions, how would you go about calculating the electric-charge density distribution p(r) for that electric field?
One nice formula you might try applying is one of Maxwell's equations: [tex]\nabla \cdot \mathbf{E} = \frac {\rho} {\varepsilon_0}[/tex] The symbol [itex]\rho[/itex] is the charge density that generates the electric field [itex]\mathbf{E}[/itex], and [itex]\varepsilon_0[/itex] is a proportionality constant called the permittivity of free space.