A circular coil of 16 turns and radius $10\;cm$ carrying a current of $0.75 \;A$ rests with its plane normal to an external field of magnitude $5.0 \times 10^{-2}\;T$ The coil is free to turn about an axis in its plane perpendicular to the field direction , When the coil is turned slightly and released it oscillates about its stable equilibrium with a frequency of $2.0 m/s$ . What is the moment of inertia of the coil about its axis of rotation ?

Question

$\begin{array}{1 1} 1.2 \times 10^{-4}\;kg\; m^2 \\ 1.2 \times 10^{4}\;kg\; m^2 \\ 1.2 \times 10^{-2}\;kg\; m^2 \\ 1.2 \times 10^{3}\;kg\; m^2 \end{array} $