What is the maximum radiation level allowed from a radioactive source when measuring less than 4 inches from the sealed source?

In radiation safety and measurement, the maximum radiation level permitted from a sealed radioactive source is crucial for ensuring the safety of individuals working near such materials. When measuring the radiation levels, distances from the source are a key factor because radiation intensity diminishes with distance—a principle known as the inverse square law.

When the question specifies measuring less than 4 inches from the sealed source, it implies that the proximity to the source would likely yield a higher radiation reading than at a distance of six inches. The answer of 50 mR/hr at six inches is most reasonable as a maximum limit because it reflects a level that is low enough to provide a margin of safety, but still acknowledges the potential for higher exposure rates as you get closer to the source.

The option that indicates 50 mR/hr strikes a balance between allowing the use of radioactive sources while ensuring that those who handle or are near them do not exceed exposure limits set by safety regulations. In actual practice, specific occupational exposure limits may vary based on regulations, but maintaining a low maximum radiation level is essential to protect personnel from the potential health effects of radiation.

Understanding these parameters is essential in the context of radiation safety protocols and guidelines that are designed to minimize risks associated with exposure to radioactive materials.