- Ionizing power is the ability of radiation to produce ions (charged particles) by removing electrons from atoms or molecules in the medium it passes through. - Alpha (α) particles are helium nuclei (2 protons, 2 neutrons) and carry a +2 charge. Due to their relatively large mass and high charge, they interact strongly with matter, causing intense ionization over a very short range. - Beta (β) particles are electrons or positrons (-1 or +1 charge). They are much lighter and faster than alpha particles, interact less strongly, and penetrate further, causing less ionization per unit path length than alpha particles. - Gamma (γ) rays and X-rays are electromagnetic radiation (photons) and are uncharged. They interact with matter primarily through the photoelectric effect, Compton scattering, or pair production, which then produce energetic electrons that cause ionization. Their ionizing power is generally lower than charged particles like alpha or beta, but they have much greater penetrating power. - Comparing the listed options, Alpha rays have the highest ionizing power.