Magnetism And Matter

The magnetic moment and moment of inertia of a magnetic needle as shown are, respectively, \(1.0 \times 10^{-2} \mathrm{~A} \mathrm{~m}^2\) and \(\frac{10^{-6}}{\pi^2} \mathrm{~kg} \mathrm{~m}^2\). If it completes 10 oscillations in \(10 \mathrm{~s}\), the magnitude of the magnetic field is