A small uncharged conducting sphere is placed in contact with an identical sphere but having \( 4 \times 10^{-8} \, \text{C} \) charge and then removed to a distance such that the force of repulsion between them is \( 9 \times 10^{-3} \, \text{N} \). The distance between them is (Take \( \frac{1}{4\pi \varepsilon_{0}} \) as \( 9 \times 10^{9} \) in SI units)
