An electron fired as a straight line from point A, located at 30?m from the center of a spherical atom of radius 10m and travelling

An electron fired as a straight line from point A, located at 30?m from the center of a spherical atom of radius 10µm and travelling towards it at the rate of 1 m/sec barely grazes the periphery of the atom. How much time is needed for the electron to move from point A till it tangentially grazes the atom?