Which statement about alpha radiation is accurate?

Which statement about alpha radiation is accurate?

• A. They are highly penetrating radiation
• B. They have the least penetrating ability
• C. They require shielding only in space
• D. They are not hazardous to humans

Answer: (B)

Alpha radiation consists of helium nuclei, which are heavy and carry a positive charge. Because of their mass and charge, they lose energy quickly in matter and have very limited range, so they cannot penetrate far. A sheet of paper or just the outer layer of skin can stop them, making their external penetrating ability the least among common radiation types. They are not hazardous to humans from a distance, but can be dangerous if the material is ingested or inhaled, since inside the body they deposit a lot of energy in a small area. The other statements aren’t accurate: alpha radiation is not highly penetrating, shielding is needed in many environments (not only in space), and they can be hazardous if internalized. Therefore, the statement that alpha radiation has the least penetrating ability is the best description.

Alpha radiation consists of helium nuclei, which are heavy and carry a positive charge. Because of their mass and charge, they lose energy quickly in matter and have very limited range, so they cannot penetrate far. A sheet of paper or just the outer layer of skin can stop them, making their external penetrating ability the least among common radiation types. They are not hazardous to humans from a distance, but can be dangerous if the material is ingested or inhaled, since inside the body they deposit a lot of energy in a small area. The other statements aren’t accurate: alpha radiation is not highly penetrating, shielding is needed in many environments (not only in space), and they can be hazardous if internalized. Therefore, the statement that alpha radiation has the least penetrating ability is the best description.