Question: An alpha particle (α), which is the same as a helium-4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of âˆ'3.45Ã-10âˆ'3 V . The charge and the mass of an alpha particle are qα = 3.20Ã-10âˆ'19 C and mα = 6.68Ã-10âˆ'27 kg , respectively. What is the final velocity of the alpha particle, (vf)α?