Which type of radiation is categorized as very weak and can be stopped by the skin?

Alpha radiation is categorized as very weak and can be easily stopped by the outer layer of human skin. This type of radiation consists of helium nuclei, which are relatively large compared to other forms of radiation. Due to their size and charge, alpha particles cannot penetrate the skin and are only harmful if ingested or inhaled. This characteristic makes alpha radiation significantly less dangerous in terms of external exposure.

In contrast, beta radiation, while more penetrating than alpha radiation, can be stopped by materials such as plastic or glass; gamma radiation is highly penetrating and requires dense materials like lead for shielding; and x-ray radiation also penetrates tissue and requires similar protective measures. Understanding these differences is essential for safe handling of materials that may emit radiation in emergency medical settings.