question_answer

In a certain region of space electric field \[\vec{E}\] and magnetic field \[\vec{B}\] are perpendicular to each other and an electron enters in region perpendicular to the direction of \[\vec{B}\] and \[\vec{E}\] both and moves undeflected, then velocity of electron is:                                                                                                         [AIPMT 2001]

A) \[\frac{|\vec{E}|}{|\vec{B}|}\]      

B)  \[\vec{E}\times \vec{B}\]  

C)   \[\frac{|\vec{B}|}{|\vec{E}|}\]            

D)  \[\vec{E}.\vec{B}\]