A uniform electric field E is present horizontally along the paper throughout region but uniform magnetic field `B_(0)` is present horizontally (perpendicular to plane of paper in inward direction) right to the line AB as shown.A charge particle having charge q and mass m is projected vertically upward and crosses the line AB after time` t_(0) `.Find the speed of projection if particle moves after t_(0) with constant velocity.(given `qE=mg) qquad A (1)/(q) (1)/(m) `