[" Two similar metal spheres are "],[" separated by silk threads form "],[" the same point.When the "],[" spheres are given equal "],[" charge of "2 mu c" the distance "],[" between them becomes "6cm.],[" If length of each thread is "],[5cm," the mass of each sphere "],[" is (acceleration due to gravity "],[g=10m/s^(2))],[" F "]