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 x-y 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 milliseconds with a velocity $$\overrightarrow{u}_2 = 2\left(\sqrt 3 \widehat{i} + \widehat{j}\right) ms^{-1}$$. The correct statement(s) is (are)