A \(100\) turn closely wound circular coil of radius \(10~\text{cm}\) carries a current of \(3.2~\text{A}\). the magnetic moment of this coil is:
1. \(20~\text{A-m}^2\)
2. \(10~\text{A-m}^2\)
3. \(30~\text{A-m}^2\)
4. \(15~\text{A-m}^2\)$\mathrm{}$