Chemistry question

Question

According to measurements, most people's exposure to naturally-occurring background radiation comes from what source?

1. smoke detectors
2. X-rays
3. radon gas
4. nuclear power plants
5. medical waste

Answer 1

Smoke detectors, nuclear power plants and medical waste are not naturally occurring sources of radiation, so those don't fit the question. There are naturally occurring sources of x-rays, such as cosmic radiation and x-rays generated by the Compton effect during radioactive decay but our exposure to those is low. The greatest source of exposure to naturally occurring radiation on this list is radon gas.