Which of the following is not a
natural source of nuclear radiation? (A) Earth, (B) a nuclear power
station, (C) the Sun.
The question asks about types of
nuclear radiation sources. The question asks which of the
options given is not a natural source of nuclear radiation. If something is not a natural
source of radiation, it must be an artificial source. This means people have done
something to the source to change how much nuclear radiation it emits.
The Earth is radioactive. More accurately, some rocks in the
Earth are radioactive. These rocks have not been affected
by people to make them radioactive; they are naturally radioactive. The Sun is radioactive. The Sun has not been affected by
people to make it radioactive; it is naturally radioactive. A nuclear power station contains
radioactive material. This material is naturally
radioactive. However, in the power station,
people do things to the radioactive material that makes its nuclei more likely to
decay. And so the radioactive material
decays quicker than it normally would.
We see then that the nuclear
radiation from a nuclear power station is emitted due to changes made by people,
which means by artificial changes. The correct answer is option (B), a
nuclear power station.