Two small spherical balls each carrying a charge $Q = 10\mu C$ (10 micro-coulomb) are suspended by two insulating threads of equal lengths 1m each, from a point fixed in the ceiling. It is found that in equilibrium threads are separated by an angle ${60^o}$ between them, as shown in the figure. What is the tension in the threads (Given: $\frac{1}{{(4\pi {\varepsilon _0})}} = 9 \times {10^9}Nm/{C^2}$)