A scientist has two radioactive substances. One emits beta particles, and the other emits alpha particles. He thinks that since the alpha particles are larger, they are more dangerous to humans. What is wrong with his reasoning?

Question

welshfella · Answer

Alpha rays are less dangerous because they only travel a few centimeters from the source i air and can be stopped by a piece of paper or your clothing, whereas beta rays are more penetrating and can travel 10's of centimeters.