What is measured by gray/rad?

Gray (Gy) and rad (radiation absorbed dose) are units used to quantify the amount of ionizing radiation absorbed by a material, particularly human tissue. This absorbed dose reflects the energy deposited in the material per unit mass and is a crucial measure in assessing potential biological effects of radiation exposure.

Measured in grays or rads, absorbed dose is significant in radiation safety because it correlates directly with the biological response to radiation. Different tissues can absorb radiation differently, and the absorbed dose helps to understand the risk of radiation effects such as cancer and other health issues. Thus, the correct answer emphasizes the relationship between dose and biological impact, making it imperative in establishing safety standards and guidelines.

The other options address relevant concepts in radiation safety, but they do not focus specifically on the quantity indicated by gray/rad. For instance, radiation exposure typically refers to the amount of radiation that may reach a person or environment, while exposure time relates to how long someone is subjected to radiation. Intensity of radiation describes how much radiation is emitted from a source without directly relating to the absorbed dose in a target.