An electrostatic air purifier comprising two horizontal plates each 15 cm × 15 cm is employed to remove smoke particles from the air injected between the plates. The air purifier first ionizes the particles, then passes the air through a region with a uniform electric field, perpendicular to the airflow direction, to deflect the charged particles towards a collection plate. If the smoke particles are charged with 100 extra electrons and the air flows at a speed of 2.5 m/s, what minimum electric field strength is required to deflect the smallest smoke particle by 5.0 mm before it reaches the collection plate? Assume negligible air resistance and gravity. The mass of each smoke particle is 4.0 × 10^-11 g.