Video Transcript
Which of the following most
correctly defines a radioactive object? (A) A radioactive object must have
emitted nuclear radiation. (B) A radioactive object must have
absorbed nuclear radiation. (C) A radioactive object must
contain atoms that can emit nuclear radiation.
Say that we have some object and we
want to determine if this object is radioactive. An object is radioactive if it’s
capable of emitting nuclear radiation. Nuclear radiation comes from atoms
as they change from one type of atom to another. So for an object to be able to give
off radiation, it has to have at least one of these unstable atoms. If it does, we know that at some
point, this object will give off nuclear radiation. Considering our three answer
options, option (A) says a radioactive object must have emitted nuclear
radiation. If an object gave off this
radiation in the past, then it was radioactive. But that doesn’t mean it still is
now.
On the other hand, an object that
has absorbed nuclear radiation isn’t necessarily able to emit radiation itself. As we’ve seen, it’s this emission
of radiation that defines a radioactive object. Our answer choice then is option
(C). A radioactive object must contain
atoms that can emit nuclear radiation.
