NMT UPDATED FINAL EXAM QUESTIONS AND
CORRECT ANSWERS
Which Statement about the half-life of a radionuclide is correct?
A) It is the time it takes for the radioactive source to become stable
B) It is half the time it takes for an atom to decay
C) It is half the time it takes the activity of the source to decrease to zero
D) It is the time it takes the activity of the source to decrease by half - CORRECT
ANSWERS D) It is the time it takes the activity of the source to decrease by half
What does the x - axis in the following graph represent?
A) Number of half-lives
B) Number of decays
C) Number of disintegration
D) Number of atoms in a sample - CORRECT ANSWERS A) Number of half-lives
Two individuals are exposed to 10mGy of radiation. Individual A was exposed to high harm
radiations across his entire body. Individual B was exposed to a low harm radiation across a
single organ system. Which unit(s) are best to use in comparing furute risk(s) of cancer?
A) rem
B) becquerel
C) rad
D) roentgen - CORRECT ANSWERS A) rem
,What happens to the half-life of a radioactive substance as it decays?
A) It behaves randomly
B) It remains constant
C) It increases
D) It decreases - CORRECT ANSWERS B) It remains constant
What do we mean when we say that " radioactive decay is random?"
A) We cannot predict which element will be radioactive
B) We cannot predict the average decay rate of a radioactive material
C) We cannot predict when an individual atom with in a group of radioactive nuclei will decay
D) We cannot predict when a radioactive material will reach background levels of radiation -
CORRECT ANSWERS C) We cannot predict when an individual atom with in a group of
radioactive nuclei will decay
A vial of generator eluate contains 432 mCi immediately following elution. How many mCi will
remain 8 hrs later?
A) 172 mCi
B) 1,085 mCi
C) 257 mCi
D) 86 mCi - CORRECT ANSWERS A) 172 mCi
All of. the following are International System (SI) units, EXCEPT:
A) gray (Gy)
B) sievert (Sv)
,C) becquerel (Bq)
D) millicurie (mCi) - CORRECT ANSWERS D) millicurie (mCi)
Which of the following measures of dose combines absorbed dose with the medical effects of
varying types of radiation?
A) tissues dose
B) equivalent dose
C) effective dose
D) absorbed dose - CORRECT ANSWERS B) equivalent dose
A 10mCi dose of radionuclide would be equal to wha activity in becquerels?
A) 37 Bq
B) 3.7 Bq
C) 370 MBq
D) 37 MBq - CORRECT ANSWERS C) 370 MBq
I-123 has a half-life of 13hrs. A sample of material had an activity of 5.6 mCi at noon today.
What was its activity at noon yesterday? (decay factor = 3.526)
A) 15 mCi
B) 20 mCi
C) 10 mCi
D) 25 mCi - CORRECT ANSWERS B) 20 mCi
, A dose equivalent of 20 mSv is equal to
A) 1 rem
B) 2 rem
C) 1 mrem
D) 2 mrem - CORRECT ANSWERS B) 2 rem
The half-life or a radioactive substance is the time it takes:
1. to decay to one -half its original activity
2. to deliver one-half of its radiation dose
3. for the number of radioactive nuclei to decrease by one-half
A) 1,2 & 3
B) 1 only
C) 1 & 2
D) 3 only - CORRECT ANSWERS A) 1,2 & 3
Which of the following units describes the amount of radiation traveling through the air?
A) rad
B) curies
C) roentgen
D) rem - CORRECT ANSWERS C) roentgen
CORRECT ANSWERS
Which Statement about the half-life of a radionuclide is correct?
A) It is the time it takes for the radioactive source to become stable
B) It is half the time it takes for an atom to decay
C) It is half the time it takes the activity of the source to decrease to zero
D) It is the time it takes the activity of the source to decrease by half - CORRECT
ANSWERS D) It is the time it takes the activity of the source to decrease by half
What does the x - axis in the following graph represent?
A) Number of half-lives
B) Number of decays
C) Number of disintegration
D) Number of atoms in a sample - CORRECT ANSWERS A) Number of half-lives
Two individuals are exposed to 10mGy of radiation. Individual A was exposed to high harm
radiations across his entire body. Individual B was exposed to a low harm radiation across a
single organ system. Which unit(s) are best to use in comparing furute risk(s) of cancer?
A) rem
B) becquerel
C) rad
D) roentgen - CORRECT ANSWERS A) rem
,What happens to the half-life of a radioactive substance as it decays?
A) It behaves randomly
B) It remains constant
C) It increases
D) It decreases - CORRECT ANSWERS B) It remains constant
What do we mean when we say that " radioactive decay is random?"
A) We cannot predict which element will be radioactive
B) We cannot predict the average decay rate of a radioactive material
C) We cannot predict when an individual atom with in a group of radioactive nuclei will decay
D) We cannot predict when a radioactive material will reach background levels of radiation -
CORRECT ANSWERS C) We cannot predict when an individual atom with in a group of
radioactive nuclei will decay
A vial of generator eluate contains 432 mCi immediately following elution. How many mCi will
remain 8 hrs later?
A) 172 mCi
B) 1,085 mCi
C) 257 mCi
D) 86 mCi - CORRECT ANSWERS A) 172 mCi
All of. the following are International System (SI) units, EXCEPT:
A) gray (Gy)
B) sievert (Sv)
,C) becquerel (Bq)
D) millicurie (mCi) - CORRECT ANSWERS D) millicurie (mCi)
Which of the following measures of dose combines absorbed dose with the medical effects of
varying types of radiation?
A) tissues dose
B) equivalent dose
C) effective dose
D) absorbed dose - CORRECT ANSWERS B) equivalent dose
A 10mCi dose of radionuclide would be equal to wha activity in becquerels?
A) 37 Bq
B) 3.7 Bq
C) 370 MBq
D) 37 MBq - CORRECT ANSWERS C) 370 MBq
I-123 has a half-life of 13hrs. A sample of material had an activity of 5.6 mCi at noon today.
What was its activity at noon yesterday? (decay factor = 3.526)
A) 15 mCi
B) 20 mCi
C) 10 mCi
D) 25 mCi - CORRECT ANSWERS B) 20 mCi
, A dose equivalent of 20 mSv is equal to
A) 1 rem
B) 2 rem
C) 1 mrem
D) 2 mrem - CORRECT ANSWERS B) 2 rem
The half-life or a radioactive substance is the time it takes:
1. to decay to one -half its original activity
2. to deliver one-half of its radiation dose
3. for the number of radioactive nuclei to decrease by one-half
A) 1,2 & 3
B) 1 only
C) 1 & 2
D) 3 only - CORRECT ANSWERS A) 1,2 & 3
Which of the following units describes the amount of radiation traveling through the air?
A) rad
B) curies
C) roentgen
D) rem - CORRECT ANSWERS C) roentgen
