question_answer

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