A bar magnet has a magnetic moment equal to\[5\times {{10}^{-5}}weber\times m.\] It is suspended in a magnetic field which has a magnetic induction equal to \[8\pi \times {{10}^{-4}}tesla.\] The magnet vibrates with a period of vibration equal to 15 sec. The moment of inertia of the magnet is [MP PMT 1993; CBSE PMT 2001]

• A.            \[22.5kg\times {{m}^{2}}\]    
• B.            \[11.25\times kg\times {{m}^{2}}\]
• C.            \[5.62\times kg\times {{m}^{2}}\]                                  
• D.            \[7.16\times {{10}^{-7}}kg-{{m}^{2}}\]