Q10. Two identical conducting spheres $P$ and $S$ with charge $Q$ on each, repel each other with a force 16 N . A third identical uncharged conducting sphere $R$ is successively brought in contact with the two spheres. The new force of repulsion between P and S is :\\
(1) 1 N\\
(2) 6 N\\
(3) 12 N\\
(4) 4 N