Which type of radiation is not very penetrating, yet highly ionizing and can be represented by a helium-4 nucleus?

Which type of radiation is not very penetrating, yet highly ionizing and can be represented by a helium-4 nucleus?

• A. Gamma radiation
• B. Beta decay
• C. Alpha decay
• D. X-ray

Answer: (C)

Alpha radiation is made of helium-4 nuclei, which are two protons and two neutrons. Its heavy mass and double positive charge cause strong interactions with matter, so it loses energy quickly and produces many ion pairs along a very short path. This makes it highly ionizing. Yet because of its size and charge, it doesn’t penetrate far—stopped by a sheet of paper or a few centimeters of air. In contrast, gamma rays and X-rays are electromagnetic and penetrate much more deeply with less dense ionization, while beta particles (fast electrons) are lighter and penetrate more than alpha but less than gamma. So the described radiation is alpha, represented by a helium-4 nucleus.

Alpha radiation is made of helium-4 nuclei, which are two protons and two neutrons. Its heavy mass and double positive charge cause strong interactions with matter, so it loses energy quickly and produces many ion pairs along a very short path. This makes it highly ionizing. Yet because of its size and charge, it doesn’t penetrate far—stopped by a sheet of paper or a few centimeters of air. In contrast, gamma rays and X-rays are electromagnetic and penetrate much more deeply with less dense ionization, while beta particles (fast electrons) are lighter and penetrate more than alpha but less than gamma. So the described radiation is alpha, represented by a helium-4 nucleus.