Which traditional unit is described as equivalent to 100 ergs/g of irradiated material?

• A. Gray
• B. Rad
• C. rem
• D. Roentgen

Answer: (B)

The traditional unit that is equivalent to 100 ergs per gram of irradiated material is the rad. The rad is a unit of absorbed radiation dose, defining the amount of energy deposited by ionizing radiation in a given mass of tissue. More specifically, one rad represents the absorption of 100 ergs of energy per gram of substance.

In practical terms, this means that when 100 ergs of energy are imparted to each gram of a specific type of irradiated material, it is quantitatively described as receiving a dose of one rad. This definition is essential in radiation therapy and radiological assessments, where accurate dose measurement is critical for both safety and treatment efficacy.

While other units like the gray (which is the SI equivalent of the rad) and the rem (which factors in biological effect) are important in radiation measurements, they serve different purposes and are based on different parameters related to radiation exposure and biological impact. Understanding the concept of the rad as a measure of absorbed dose helps differentiate it from these other units, which are used in varying contexts within radiobiology and radiation safety.