A small sphere carrying \(6.0 \mathrm{nC}\) of charge is placed \(100 \mathrm{~mm}\) from a small sphere carrying \(3.0 \mathrm{nC}\) of charge. Assume the spheres are tiny relative to the \(100-\mathrm{mm}\) separation distance. At what position on the line joining the spheres is the electric field magnitude zero?