A beam of charged particle, having kinetic energy `10^3 eV`, contains masses `8xx10^(-27) kg and 1.6xx10^(-26) kg` emerge from the end of an accelerator tube. There is a plate at distance `10^2 m` from the end of the tube and placed perpendicular to the beam. Calculate the magnitude of the smallest magnetic field which can prevent the beam from striking the plate.
