Question
A charged particle with charge q enters a region of constant ,uniform and mutually orthogonal fields E and B with a velocity v perpendicular in both E and B , and comes out without any change in magnitude or direction of v. Then (a)v=E×B/|B|² (b)v=B×E/|B|² (c)v=E×B/|E|² (d)v=B×E/|E|² (here qantities in options which are not enclosed in square brackets are in vector form)