Two point-like objects of masses 20 gm and 30 gm are fixed at the two ends of a rigid massless rod of length 10 cm . This system is suspended vertically from a rigid ceiling using a thin wire attached to its center of mass, as shown in the figure. The resulting torsional pendulum undergoes small oscillations. The torsional constant of the wire is $1.2 \times 10^{-8} \mathrm{~N} \mathrm{~m} \mathrm{rad}^{-1}$. The angular frequency of the oscillations in $n \times 10^{-3} \mathrm{rad} \mathrm{s}^{-1}$. The value of $n$ is $\_\_\_\_$ .