Video Transcript
Which of the following statements
correctly relates the exposure time of a person to a radioactive object, the rate at
which the object emits nuclear radiation, and the absorbed radiation dose for the
person? (A) The absorbed radiation dose
will increase only if the exposure time increases. (B) The absorbed radiation dose
will increase only if the rate of emission of nuclear radiation increases. (C) The absorbed radiation dose
will increase if either the exposure time or the rate of emission of nuclear
radiation increases.
This question is asking us about
the radiation dose, or the total amount of nuclear radiation, absorbed by a person
that is exposed to a radiation source. Let’s start by discussing the
statement proposed by each answer option.
Option (A) mentions a correlation
between absorbed radiation dose and exposure time. Now, it is true that the more time
a person is exposed to radiation, the more radiation that person will absorb. However, it’s important to notice
here the word “only.” While increased exposure time does
increase the absorbed radiation dose, it’s definitely not the only factor that
contributes to how much radiation is absorbed. Option (A) therefore cannot be
correct.
Now, option (B) mentions a
correlation between absorbed radiation dose and the rate of emission of nuclear
radiation. It makes sense that if a person is
near a source of radiation that has a greater rate of emission, then the person will
receive a greater dose of radiation within the same period of time. Again, though, we should notice the
word “only.” The rate of emission of nuclear
radiation is not the only factor to take into consideration. After all, we’ve already seen that
the dose will increase if the exposure time increases. So, we know that option (B) is not
correct.
This leaves option (C), which says
that both the exposure time and rate of emission of radiation are important. We’ve seen that increasing either
the exposure time or the emission rate will increase the absorbed dose. We can therefore identify option
(C) as being the correct answer. The absorbed radiation dose will
increase if either the exposure time or the rate of emission of nuclear radiation
increases.
