Question

6) 0.45 e/hr doo.is rhr 2. An individual with a 20 gram thyroid has an up take of 0.3 uCi by ingestion of a radionuclide of 1.o MeV What is the Committed Dose Equivalent to the thyroid if the etTective halr-life is 60 days? that decays by beta particle emission 100% of the time with a max. beta a) 66 rem 22 rem c) 0.26 rem d) none of the above 3. Because of the nature of radioactive material, the types used to prevent internal and external personnel contamination difters greatly from that which would be used to protect someone from of personal protective equipment of chemical agents 5 false ) tie 4. Which of the following statements about the committed dose is incorrect? It is a function of the effective half-life. It is the same whether the total uptake is in a single event or over several smaller events during the year It is assigned to the individual's dose records in the year in which the uptake(s) occur It is a function of the radiotoxicity a) b) c) d) S. Which of the following would be the best material for shielding neutrons? a) lead b) aluminum c) paper dDparaffin 6. How long can a worker stay in a 4.5 rem/hr radiation area and not exceed 100 mrem? c) 0.0222 min a) 22.2 min. b) 1.33 min 22.2 hr You are standing 5 feet from a source emitting 0.5 Me V gamma rays that is in a 1.5 em thick lead 7. shield; the exposure rate is 2 mR/hr. What will the exposure rate be if the source is removed from its shield? a) 0.06 mR/hr b) 31 mR/hr c) 15.6 mR/hr d) 0.13 mR/hr

Answer 1

3. B) True ,The personal protective equipments used for the protection from radioactive materials is different from that used for other chemical agents . Examples of PPE used in radioactive materials are - personal radiation dosimeter , HEPA filters etc.

4. C) it is assigned to the individuals dose record in the year in which the uptake occurs is the incorrect option . Committed dose is the measure of the probability of cancer and genetic damage due to low levels of radiation.

5.D) The best material to shield neutron is paraffin . Paraffin are hydrocarbons and it is able to slow down neutrons as it contains light atoms like hydrogen etc .

6. Stay time = Dose limit ( mrem)/ Amount of radiation getting (mrem / hr)

= 4.5rem to mrem = 4.5 ×1000= 4500

1rem = 1000 mrem

Dose limit = 100 mrem

Amount of radiation getting is 4500 mrem

Hence , stay time = 100 mrem/ 4500mrem

= 0.0222min

Option B) is the correct option.