Which type of radiation is described as a helium nucleus consisting of two neutrons and two protons?

Alpha radiation is correctly identified as a helium nucleus, which consists of two protons and two neutrons. This type of radiation is a form of particulate radiation that is emitted during the decay of certain radioactive elements. Due to its composition, alpha particles have a relatively large mass and a positive charge.

In comparison to other radiation types, alpha particles have a limited ability to penetrate materials; they can be stopped by a sheet of paper or even the outer layer of human skin. However, when ingested or inhaled, alpha particles can cause significant biological damage due to their high energy and charge.

Other types of radiation, such as beta radiation, involve electrons or positrons being emitted, and neutron radiation consists of free neutrons. X-ray radiation, on the other hand, is a form of electromagnetic radiation rather than a particulate form, lacking the mass and charge characteristic of alpha particles. Understanding the fundamentals of alpha radiation is crucial for fields related to health physics and radiation safety, which are significant areas of focus in the Certified Safety Professional curriculum.