Final answer:
The claim that half of annual radiation exposure comes from natural sources and half from human-made is false. About 82% of exposure comes from natural sources, primarily radon gas, whereas human-made exposure, such as medical imaging, constitutes the rest.
Step-by-step explanation:
The statement that most people receive approximately half their annual radiation exposure from natural sources and half from human-made sources is false. According to various data sources, about 82% of a person's annual radiation exposure is due to natural radiation sources. For an average adult in the United States, the natural radiation dose is about 150-600 mrem per year, with radon gas accounting for more than half of an individual's total exposure. Other sources of natural radiation include cosmic rays and terrestrial sources. On the other hand, human-made sources, such as medical imaging and treatments, contribute to the remaining percentage of radiation exposure.
It's important to note that the exact percentage can vary based on several factors such as altitude, geographic location, lifestyle, and medical procedures undergone. For instance, individuals at higher altitudes are exposed to more cosmic radiation, and those requiring medical imaging may receive additional radiation from those procedures.