Magnetism

A particle of mass M and positive charge Q, moving with a constant velocity \({\overrightarrow u _1} = 4\widehat i\) ms^\(-\)1 enters a region of uniform static magnetic field, normal to the xy plane. The region of the magnetic field extends from x = 0 to x = L for all values of y. After passing through this region, the particle emerges on the other side after 10 ms with a velocity \({\overrightarrow u _2} = 2\left( {\sqrt 3 \widehat i + \widehat j} \right)\) ms^\(-\)1. The correct statement(s) is(are)