An electron (mass = 9.0×\[{{10}^{-31}}\]kg and charge =\[1.6\times {{10}^{-19}}\]coulomb) is moving in a circular orbit in a magnetic field of \[1.0\times {{10}^{-4}}\,weber/{{m}^{2}}.\] Its period of revolution is [MP PET 2000; Pb PET 2003]

• A.             \[3.5\times {{10}^{-7}}\]sec 
• B.            \[7.0\times {{10}^{-7}}\]sec
• C.            \[1.05\times {{10}^{-6}}\]sec
• D.            \[2.1\times {{10}^{-6}}\]sec