Video Transcript
Which of the following is an example of ionizing radiation? (A) IR rays, (B) cosmic rays, (C) light rays, (D) microwaves, or (E) radio waves.
Ionizing radiation is radiation that carries enough energy to remove electrons from atoms. Looking at the electromagnetic spectrum, we can separate radiation into ionizing and nonionizing in the ultraviolet or UV range. We can see from the spectrum that option (A), IR rays or infrared rays, is in the nonionizing part of the spectrum. So it is not an example of ionizing radiation, and it cannot be the answer to this question. The same is true for option (C) light rays. Light rays or visible light are also nonionizing. So option (C) is not the answer to this question. The same is true for option (D) and option (E). Microwaves and radio waves are nonionizing. So neither option (D) nor (E) can be the answer to this question.
We are left with option (B) cosmic rays. Cosmic rays are high-energy protons and atomic nuclei originating from outer space that travel at almost the speed of light. Cosmic rays are a type of particle radiation, along with alpha particles, beta particles, and free neutrons. All of these types of particle radiation are ionizing. So the answer to the question “Which of the following is an example of ionizing radiation?” is (B) cosmic rays.
