An alpha particle is moving at a speed of 5.45 x105 m s- through a velocity selector and mass spectrometer in a direction perpendicular to the shared uniform magnetic field. The electric field strength of the velocity selector is 12.0 x106 N/C. The charge of an alpha particle is 3.22 x 10-1 C and its mass is 6.64 10-27 kg. Calculate the radius of the path of the alpha particle in the mass spectrometer. Solution: State the strength of the magnetic field, using the correct units: State the radius of the curve the alpha particle takes in the analyser part of the spectrometer, including the correct units: