What is the range of the film badge measured in?

The film badge, which is used to monitor an individual's exposure to ionizing radiation, typically measures the dose of radiation in units of REM, which stands for Roentgen Equivalent Man. While the options include other units like RAD (Radiation Absorbed Dose), GRAY (a measure of absorbed dose equivalent), and SV (Sievert, another unit related to dose equivalent), the specific measure used for film badges is based on how much radiation the film is exposed to, ultimately converting the measurements into REM for the purpose of assessing the dose received by personnel.

Film badges work by utilizing a photographic film that darkens when exposed to radiation; the degree of darkening correlates to the amount of radiation received. The results are ultimately calculated and reported in terms of REM, which considers the biological effects of the radiation on human tissue, making it a relevant measure for assessing potential health impacts from exposure.

Thus, the most appropriate answer in this context is that a film badge measures radiation exposure in REM.