Effects of Radiation Exposure, NRC 10
CFR 20 AND 35 All Questions With
Correct And Verified Answers
\.Average energy of a positron emitted during positron decay? - Answer- 4/10 or 0.4 of the
maximum energy.
\.1 WLM = ? - Answer- 1 rem CEDE
\.Radiation exposure to miners is regulated by? - Answer- 30 CFR
\.Maximum dose allowed to miners is? - Answer- 4 WLM per year
\.A geiger counter has enough voltage to cause? - Answer- Secondary electrons with a long
range avalanche
\.What type of decay "competes" with positron decay? - Answer- Electron capture
\.A gas-filled detector is collecting 100% of the ion pairs produced. It is said to be operating in
what region? - Answer- Ionization
\.Which laser wavelength is considered a retina hazard for safety purposes? - Answer- 400 to
1400 nm
,\.To achieve secular equilibrium, which of the following conditions must be met? - Answer-
Parent half-life >>> Daughter half-life
\.What is the limit for external surface contamination on a DOT package? - Answer- 22
dpm/cm^2
\.The threshold limit value (TLV) for exposure to radiation from a microwave oven is? - Answer-
10 mW/cm^2
\.Tissue dose from thermal neutrons occurs principally as a result of? - Answer- (n, gamma)
reactions with hydrogen and (n,p) reactions with nitrogen
\.What are the value(s) for gas amplification factors in ionization chambers? - Answer- Equal
to 1
\.What is the clearance time for a particulate traveling through the trachea? - Answer- 0.1
hour
\.What is the clearance time for a particulate traveling through the bronchi? - Answer- 1.0
hour
\.What is the clearance time for a particulate traveling through the bronchioles? - Answer-
4.0 hours
\.What is the clearance time for a particulate traveling through the alveoli? - Answer- 10 to
1500+ days
,\.In a semi-infinite cloud of gamma-emitting noble gasses, the gamma contribution to the
absorbed dose rate can be estimated as? - Answer- D = 0.25EX ; D = rads/sec or rem/sec, E =
gamma energy (MeV) * yield , X = concentration (uCi/cc)
\.What are the 4 major types of cells in circulating blood? - Answer- Erythrocytes,
Lymphocytes, Granulocytes, Platelets
\.What are the purpose of erythrocytes? - Answer- Oxygen transport to the cells
\.What are the purpose of lymphocytes? - Answer- Generate antibodies to fight infection
\.What are the purpose of granulocytes? - Answer- Fight infection by phagocytosis
\.What are the purpose of platelets? - Answer- Blood clotting agent and vessel integrity
\.How do you calculate RBE? - Answer- Dose of 250 kVp x-Rays / Dose of other radiation
\.What is the current value for LD50/60 in humans? - Answer- 410 rem whole body with no
medical intervention
\.At what exposure level does Gastrointestinal Syndrome start? - Answer- 1000 rem
\.At what exposure level does Cerebrovascular Syndrome start? - Answer- 5000 rem
\.What level of exposure produces temporary sterility? - Answer- 250 rem
, \.What level of exposure produces permanent sterility? - Answer- 500 rem
\.What are the 3 categories of somatic (late) effects of radiation? - Answer- Life shortening,
leukemia, and other cancers.
\.What was the result of the BEIR V committee? - Answer- "Health Effects of Exposure to Low
Levels of Ionizing Radiation"
\.What is the protection factor (PF) for a full-face, negative-pressure, SCBA? - Answer-
Negative Pressure - 50
\.What is the protection factor (PF) for a full-face, pressure-demand (positive pressure), SCBA? -
Answer- Positive Pressure - 10,000
\.What is the protection factor (PF) for a full-face, demand (negative pressure during inhalation),
air-line respirator? - Answer- Demand - 100
\.What is the protection factor (PF) for a full-face, continuous-flow, air-line respirator? - Answer-
Continuous Flow - 1,000
\.What is the protection factor (PF) for a half-mask, demand (negative pressure during
inhalation), air-line respirator? - Answer- Demand - 10
\.What is the protection factor (PF) for a half-mask, continuous-flow, air-line respirator? -
Answer- Continuous Flow-50
\.What is the protection factor (PF) for a half-mask, negative pressure, air-purifying respirator? -
Answer- Half-Mask-10