Which of the following is NOT a type of ionizing radiation?

Visible light is indeed the correct choice as it is not a type of ionizing radiation. Ionizing radiation refers to radiation that carries enough energy to dislodge electrons from atoms or molecules, thereby ionizing them.

Alpha particles, beta particles, and X-rays all possess sufficient energy to ionize atoms. Alpha particles, which consist of two protons and two neutrons, are strongly ionizing but have low penetration ability. Beta particles are high-energy, high-speed electrons or positrons that can penetrate further than alpha particles. X-rays, which are a form of electromagnetic radiation, also have the energy required to cause ionization in matter.

In contrast, visible light is part of the electromagnetic spectrum and has relatively low energy that does not have the capability to ionize atoms or molecules; it primarily interacts with them in ways that do not result in electron removal. This distinction is crucial in understanding the types of radiation and their respective effects on matter.