What does the term "sievert" measure in radiation safety?

The term "sievert" measures the biological effect of ionizing radiation on living tissue. It is a derived unit that quantifies the health effects of low levels of ionizing radiation, integrating both the amount of radiation absorbed by a specific body tissue and the effect this radiation has on the tissue. This is crucial because different types of radiation can have varying impacts on biological systems, so the sievert helps to standardize and assess the risk associated with exposure based on its potential to cause harm.

In contrast, the other choices pertain to different aspects of radiation and do not relate to the sievert. For instance, measuring the intensity of radiation relates to the rate at which radiation is emitted, while the amount of radioactive material refers to its quantity, typically measured in becquerels or curies. Additionally, the penetration power of radiation characterizes how deeply radiation can penetrate materials, which is important for shielding purposes but does not directly correlate with the biological effects assessed by the sievert. Thus, the correct understanding of the sievert emphasizes its role in evaluating the potential health risks from exposure to ionizing radiation.