NRRPT Practice Exam Questions And
All Correct Answers.
Given a gamma-energy value of 0.662 MeV, and a photon yield of 0.85 per decay, the exposure
rate at 2 yards from an unshielded 10mCi Cs-137 point source is: - Answer 0.94 mR/hour
At what radius would you post a radiation area around an 8 curie Cesium 137 (662 keV photon
energy and a photon yield of 0.85 photons/disintegration) point source? - Answer 74 feet
Which of the following is equivalent to A=Aoe^-(.693/T1/2)t? - Answer A=Ao(1/2)^(t/T1/2)
As u in the equation I=Ioe^-ux is increased - Answer photon attenuation is increased
What would the time passing between the original activity and the resultant activity have been
if the original activity was 10 Curies, the resultant activity is 5 Curies and the half-life is 5 years?
- Answer 5 years
If a floor contamination level of 666 dpm/100cm^2, in a room measuring 10 m by 10 m by 10 m,
becomes uniformly suspended in the air of the room, using the Co60Y DAC value of 1E-8 uCi/ml,
what would the DAC fraction of the air in the room be? - Answer 0.3 DAC
An atom of a radionuclide that has a low neutron to proton ratio, and an atomic rest mass
energy that is 1.02 MeV greater than the product atom's rest mass energy may decay by which
of the following? - Answer Either positron emission or electron capture
For an exclusive use vehicle that is transporting radioactive materials, radiation levels on contact
with any external surface of the vehicle must not exceed: - Answer 2.0 mSv/hour
Which radioactive decay series includes Ra-226 as one of its decay products? - Answer
Uranium
Which of the following is incorrectly defined? - Answer 10CFR20, Appendix D, US Postal
Service Regional Offices
Which of the following is not a label used for radioactive shipments? - Answer Transport
Index Label
A worker is to perform maintenance on a Reactor Coolant Pump under the following
radiological conditions; Dose rate on contact with the pump - 350 mrem/hr, Dose rate at 30 cm
, from the pump (working area dose rate) is 85 mrem/hr, and an airborne concentration of .45
DAC. She will spend a maximum of 14 hours in this area during the week. According to 10CFR20,
how is this area to be posted? - Answer Caution Radiation Area
A worker breathes air at a rate of 20 Liters/minute for 2000 hours in one calendar year. The air
contains 1 DAC of a radionuclide whose ALI is defined by the stochastic dose limit. The worker's
assigned 50 year committed effective dose equivalent is: - Answer 5 rem
An air sample is taken at a flow rate of 2cfm for 5 minutes and counted using a 10% efficient
frisker giving results of 190 ncpm...using a DAC of 3E-8 uCi/ml what is the DAC fraction of the air
sample? - Answer 0.3 DAC
The Bragg-Gray principal is based upon the relationship of: - Answer ionization of the gas in
an ionization chamber to the dose in the wall material
An approximation of the energy levels that divide the three major types of gamma radiation
interactions, photoelectric effect - Compton scattering - pair production, in lead; - Answer
200 keV and 5 MeV
The term "isokinetic sampling" refers to the procedure of using sampling velocity that is exactly
equal to the: - Answer velocity of the gas stream at the point of sampling
The most common mechanisms for neutron interaction with matter is - Answer Elastic
scattering
At 20 MeV, the dominant photon interaction(s) with tissue is (are) - Answer About equal
contributions from Compton scattering and pair production
At 25 keV, the dominant photon interaction(s) with tissue is (are) - Answer About equal
contributions from the photoelectric effect and Compton scattering
In calculating atomic energy levels, the Bohr model assumes what force binds the orbiting
electron to the nucleus? - Answer Columb
As a general rule, photoelectric absorption below 100 keV - Answer Becomes less probable as
the photon energy increases
What is the binding energy of a hydrogen atom? - Answer 13.6 eV
All Correct Answers.
Given a gamma-energy value of 0.662 MeV, and a photon yield of 0.85 per decay, the exposure
rate at 2 yards from an unshielded 10mCi Cs-137 point source is: - Answer 0.94 mR/hour
At what radius would you post a radiation area around an 8 curie Cesium 137 (662 keV photon
energy and a photon yield of 0.85 photons/disintegration) point source? - Answer 74 feet
Which of the following is equivalent to A=Aoe^-(.693/T1/2)t? - Answer A=Ao(1/2)^(t/T1/2)
As u in the equation I=Ioe^-ux is increased - Answer photon attenuation is increased
What would the time passing between the original activity and the resultant activity have been
if the original activity was 10 Curies, the resultant activity is 5 Curies and the half-life is 5 years?
- Answer 5 years
If a floor contamination level of 666 dpm/100cm^2, in a room measuring 10 m by 10 m by 10 m,
becomes uniformly suspended in the air of the room, using the Co60Y DAC value of 1E-8 uCi/ml,
what would the DAC fraction of the air in the room be? - Answer 0.3 DAC
An atom of a radionuclide that has a low neutron to proton ratio, and an atomic rest mass
energy that is 1.02 MeV greater than the product atom's rest mass energy may decay by which
of the following? - Answer Either positron emission or electron capture
For an exclusive use vehicle that is transporting radioactive materials, radiation levels on contact
with any external surface of the vehicle must not exceed: - Answer 2.0 mSv/hour
Which radioactive decay series includes Ra-226 as one of its decay products? - Answer
Uranium
Which of the following is incorrectly defined? - Answer 10CFR20, Appendix D, US Postal
Service Regional Offices
Which of the following is not a label used for radioactive shipments? - Answer Transport
Index Label
A worker is to perform maintenance on a Reactor Coolant Pump under the following
radiological conditions; Dose rate on contact with the pump - 350 mrem/hr, Dose rate at 30 cm
, from the pump (working area dose rate) is 85 mrem/hr, and an airborne concentration of .45
DAC. She will spend a maximum of 14 hours in this area during the week. According to 10CFR20,
how is this area to be posted? - Answer Caution Radiation Area
A worker breathes air at a rate of 20 Liters/minute for 2000 hours in one calendar year. The air
contains 1 DAC of a radionuclide whose ALI is defined by the stochastic dose limit. The worker's
assigned 50 year committed effective dose equivalent is: - Answer 5 rem
An air sample is taken at a flow rate of 2cfm for 5 minutes and counted using a 10% efficient
frisker giving results of 190 ncpm...using a DAC of 3E-8 uCi/ml what is the DAC fraction of the air
sample? - Answer 0.3 DAC
The Bragg-Gray principal is based upon the relationship of: - Answer ionization of the gas in
an ionization chamber to the dose in the wall material
An approximation of the energy levels that divide the three major types of gamma radiation
interactions, photoelectric effect - Compton scattering - pair production, in lead; - Answer
200 keV and 5 MeV
The term "isokinetic sampling" refers to the procedure of using sampling velocity that is exactly
equal to the: - Answer velocity of the gas stream at the point of sampling
The most common mechanisms for neutron interaction with matter is - Answer Elastic
scattering
At 20 MeV, the dominant photon interaction(s) with tissue is (are) - Answer About equal
contributions from Compton scattering and pair production
At 25 keV, the dominant photon interaction(s) with tissue is (are) - Answer About equal
contributions from the photoelectric effect and Compton scattering
In calculating atomic energy levels, the Bohr model assumes what force binds the orbiting
electron to the nucleus? - Answer Columb
As a general rule, photoelectric absorption below 100 keV - Answer Becomes less probable as
the photon energy increases
What is the binding energy of a hydrogen atom? - Answer 13.6 eV
