A closely wound solenoid of \(2000\) turns and area of cross-section as \(1.6\times10^{-4}\) m², carrying a current of \(4.0\) A, is suspended through its center allowing it to turn in a horizontal plane. The magnetic moment associated with the solenoid is:
1. \(0.18\) Am²
2. \(3.24\) Am²
3. \(1.28\) Am²
4. \(0.38\) Am²

A closely wound solenoid of \(800\) turns and area of cross-section \(2.5 \times10^{-4}~\text{m}^2\) carries a current of \(3.0~\text{A}\). If the solenoid acts like a bar magnet, then what is its associated magnetic moment?
1. \(0.6~\text{J/T}\) 
2. \(0.07~\text{J/T}\) 
3. \(0.3~\text{J/T}\) 
4. \(0.8~\text{J/T}\)