IRRSP Practice Test Questions and All
Correct Answers 2026 Updated.
The activity of a radioactive source - Answer The term "Curie" defines:
a. The exposure of a radioactive source
b. The intensity of a radioactive source
c. The activity of a radioactive source
d. The output of a radioactive source
Reddening of the skin, loss of hair, blistering - Answer Which of the following are symptoms
of an acute extremity overexposure?
a. Nausea, vomiting, diarrhea
b. Fatigue, nausea, reddening of the skin
c. Diarrhea, blistering, loss of hair
d. Reddening of the skin, loss of hair, blistering
Higher gamma ray energy from the Co-60 - Answer The reason the gamma radiation emitted
from a Cobalt-60 source is more penetrating than the gamma radiation emitted from Iridium-
192 is due to the:
a. Higher output per Curie from the Co-60
b. Longer half life of the Co-60
c. Greater intensity from the Co-60
d. Higher gamma ray energy from the Co-60
3/4 - Answer A 0.400 inch piece of lead shielding will reduce the radiation intensity from an
Iridium-192 source by:
a. 3/4
b. 1/2
c. 1/4
d. 1/8
Thick section of high atomic number material - Answer When shielding against high-energy
gamma rays, which of the following characteristics provide the most effective shield?
a. Thick section of material
b. Thick section of high atomic number material
c. Thick section of low atomic number material
, d. Thick section of low density material
2.31 R/hr - Answer The radiation intensity at 1 foot from an Iridium-192 source is 452.4 R/hr.
What is the radiation intensity at 14 feet?
a. 2.31 R/hr
b. 226.2 R/hr
c. 113.1 R/hr
d. 32.3 R/hr
C - Answer Gamma radiation can be defined as:
(Answer with A, B, C, or D)
a. Particles having the mass and charge of two protons and two neutrons emitted from the
nucleus of an unstable atom
b. Very light negatively charged particles emitted from the nucleus of an unstable atom
c. Very short wavelength electromagnetic radiation emitted from the nucleus of an unstable
atom
d. Particles emitted from an unstable atom with an energy in the range of 1 to 10 M.E.V.
Attenuation - Answer The term that describes how gamma or x-rays are reduced in intensity
when passing through shielding material is:
a. Penetration
b. Scatter
c. Reflection
d. Attenuation
5 Rem to the whole body, 50 Rem to the extremities - Answer The annual radiation exposure
limits for a radiographer or an assistant can be summarized by:
a. 1.25 Rem to the whole body, 18.75 Rem to the extremities
b. 20 Rem to the whole body, 200 Rem to the extremities
c. 5 mRem to the whole body, 50 mRem to the extremities
d. 5 Rem to the whole body, 50 Rem to the extremities
3.125 Curies - Answer A 50 Curie Cobalt-60 source has decayed 4 half lives. What is the
remaining activity?
a. 6.25 Curies
b. 3.125 Curies
c. 0.195 Curies
Correct Answers 2026 Updated.
The activity of a radioactive source - Answer The term "Curie" defines:
a. The exposure of a radioactive source
b. The intensity of a radioactive source
c. The activity of a radioactive source
d. The output of a radioactive source
Reddening of the skin, loss of hair, blistering - Answer Which of the following are symptoms
of an acute extremity overexposure?
a. Nausea, vomiting, diarrhea
b. Fatigue, nausea, reddening of the skin
c. Diarrhea, blistering, loss of hair
d. Reddening of the skin, loss of hair, blistering
Higher gamma ray energy from the Co-60 - Answer The reason the gamma radiation emitted
from a Cobalt-60 source is more penetrating than the gamma radiation emitted from Iridium-
192 is due to the:
a. Higher output per Curie from the Co-60
b. Longer half life of the Co-60
c. Greater intensity from the Co-60
d. Higher gamma ray energy from the Co-60
3/4 - Answer A 0.400 inch piece of lead shielding will reduce the radiation intensity from an
Iridium-192 source by:
a. 3/4
b. 1/2
c. 1/4
d. 1/8
Thick section of high atomic number material - Answer When shielding against high-energy
gamma rays, which of the following characteristics provide the most effective shield?
a. Thick section of material
b. Thick section of high atomic number material
c. Thick section of low atomic number material
, d. Thick section of low density material
2.31 R/hr - Answer The radiation intensity at 1 foot from an Iridium-192 source is 452.4 R/hr.
What is the radiation intensity at 14 feet?
a. 2.31 R/hr
b. 226.2 R/hr
c. 113.1 R/hr
d. 32.3 R/hr
C - Answer Gamma radiation can be defined as:
(Answer with A, B, C, or D)
a. Particles having the mass and charge of two protons and two neutrons emitted from the
nucleus of an unstable atom
b. Very light negatively charged particles emitted from the nucleus of an unstable atom
c. Very short wavelength electromagnetic radiation emitted from the nucleus of an unstable
atom
d. Particles emitted from an unstable atom with an energy in the range of 1 to 10 M.E.V.
Attenuation - Answer The term that describes how gamma or x-rays are reduced in intensity
when passing through shielding material is:
a. Penetration
b. Scatter
c. Reflection
d. Attenuation
5 Rem to the whole body, 50 Rem to the extremities - Answer The annual radiation exposure
limits for a radiographer or an assistant can be summarized by:
a. 1.25 Rem to the whole body, 18.75 Rem to the extremities
b. 20 Rem to the whole body, 200 Rem to the extremities
c. 5 mRem to the whole body, 50 mRem to the extremities
d. 5 Rem to the whole body, 50 Rem to the extremities
3.125 Curies - Answer A 50 Curie Cobalt-60 source has decayed 4 half lives. What is the
remaining activity?
a. 6.25 Curies
b. 3.125 Curies
c. 0.195 Curies
