An \[\alpha -\]particle travels in a circular path of radius 0.45 m in a magnetic field \[B=1.2\,Wb/{{m}^{2}}\] with a speed of \[2.6\times {{10}^{7}}\,m/\sec \]. The period of revolution of the \[\alpha -\]particle is

• A.            \[1.1\times {{10}^{-5}}\,\sec \]                                        
• B.            \[1.1\times {{10}^{-6}}\sec \]
• C.            \[1.1\times {{10}^{-7}}\,\sec \]                                        
• D.            \[1.1\times {{10}^{-8}}\,\sec \]