What consists of subatomic particles or electromagnetic waves that are energetic enough to remove electrons from otherwise neutral atoms or molecules, ionizing them?

• A. Ionizing Radiation
• B. Non-ionizing Radiation
• C. Acoustic Radiation
• D. Thermal Radiation

Answer: (A)

Ionizing radiation is defined by its ability to eject electrons from atoms or molecules. This requires energy high enough to overcome the binding energy of the electrons. High-energy photons such as X-rays and gamma rays, along with fast charged particles like alpha and beta particles, have enough energy to ionize. Some ultraviolet photons can ionize certain atoms, but visible light and lower-energy infrared, microwaves, and radio waves do not typically ionize and are classified as non-ionizing. Acoustic radiation involves sound waves and doesn’t ionize matter, while thermal radiation (mostly infrared heat emission) likewise isn’t considered ionizing. So the description fits ionizing radiation.