Final answer:
The statement that a film badge is useful for monitoring x-ray, gamma, and moderate to high energy beta emissions is True. The film within the badge records exposure to these types of radiation, and the degree of fogging on the film is proportional to the radiation exposure level.
Step-by-step explanation:
A film badge is a personal dosimeter used for monitoring radiation exposure from various sources, including x-ray, gamma, and moderate to high energy beta emissions. This makes the statement (A) True. The badge contains a photographic film that gets fogged when exposed to radiation. The amount of fogging indicates the level of radiation exposure. Film badges have various absorbers sandwiched with the film to determine the radiation's penetrating ability as well as the amount of exposure.
Film badges are not brand-dependent for their basic functioning and do not solely monitor x-ray emissions, so options B, C, and D are not correct. These detectors are not very sensitive to low levels of radiation and there are more sensitive systems available, which use crystals to detect radiation. However, within their operational limits, film badges are a standard tool for radiation monitoring.