a. Use a diagram to explain how the electric force on a charged particle could be used to separate a beam of electrons (e⁻) and positrons (e⁺) into two separate beams. (A positron is a positively charged particle that has the same mass as an electron but opposite charge. Positron–electron pairs are often produced in collisions in a particle accelerator.)

b. Explain how this effect could be used to separate ions that have different masses and charges.