question_answer

In a certain region of space, electric and magnetic fields are crossed:

A)  A charged particle moves unelected in the region only if\[\vec{v}\]is perpendicular to both\[\vec{E}\]and\[\vec{B}\]

B)  A charged particle must move unelected in the region, if\[\vec{v}\]is perpendicular to both\[\vec{E}\]and\[\vec{B}\]

C)  If a positron moves undefeated if its velocity is\[\vec{v}\], an electron will move unselected its velocity is\[\vec{v}\]

D)  A charged particle may move undefeated even if it is not moving with\[\vec{v}\]perpendicular to\[\vec{B}\]