A particle of mass 1 mg and charge $q$ is lying at the mid-point of two stationary particles kept at a distance 2 m when each is carrying same charge $q$. If the free charged particle is displaced from its equilibrium position through distance $x$ ($x \ll 1\mathrm{~m}$), the particle executes SHM. Its angular frequency of oscillation will be \_\_\_\_ $\times 10^{5}\mathrm{~rad~s}^{-1}$ (if $q^{2} = 10\mathrm{~C}^{2}$).