question_answer

A beam of electrons is moving with constant velocity in a region having electric and magnetic fields of strength \[20\,\,V{{m}^{-1}}\]and\[0.5T\]at right angles to the direction of motion of the electrons. What is the velocity of the electrons?

A) \[20\,\,m{{s}^{-1}}\]                      

B) \[40\,\,m{{s}^{-1}}\]

C) \[8\,\,m{{s}^{-1}}\]                        

D) \[5.5\,\,m{{s}^{-1}}\]