Magnetism And Matter

A magnetic needle has a magnetic moment of \(5 \times 10^{-2} \mathrm{~Am}^2\) and moment of inertia \(8 \times 10^{-6} \mathrm{~kgm}^2\). It has a period of oscillation of \(2 \mathrm{~s}\) in a magnetic field \(\mathbf{B}\). The magnitude of magnetic field is approximately?