Ionizing and Nonionizing Radiation and Thermal Stress Questions
Session 5 Study Questions: Physical Agents and Non-Chemical Exposure
1. A radioactive source has an intensity of 500 mr/hr at 6 feet. What is the intensity at 50
feet?
2. The half-life of Po-210 is 138.4 days. An anti-static plate is obtained with an activity of
300 µCi. What is the activity 3 years later?
3.
The half-value layer for a shielding material is 5 mm. If the intensity of the radiation
beam striking the shield is 100 R/hr and the shield is 2 inches thick, what is the intensity
is mR/hr on the other side of the shield?
4. What is the effective half-life of a radionuclide with a physical half-life of 28 hours and a
biological half-life of 50 days?
5. Based upon the ability to penetrate each of these materials, identify the type of ionizing
radiation that is represented in the spaces provided;
Thomas P. Fuller, ScD, CIH
Ionizing and Nonionizing Radiation and Thermal Stress Questions
6. A construction crew laying concrete was exposed to the following conditions: WB =
31oC, DB = 30oC, and GT = 37oC. Calculate the WBGT Index.
7. In a laundry, the following conditions were measured: WB = 94oF, DB = 93oF, and GT =
96oF. Calculate the WBGT Index. (1 pt)
8. If a worker was standing at that location what could their potential radiant exposure be?
If the beam is smaller than the limiting aperture the diameter of the limiting aperture
should be used (7mm)
Thomas P. Fuller, ScD, CIH
Ionizing and Nonionizing Radiation and Thermal Stress Questions
9. Given an MPE of 2.55 mW/cm2 for visible CW wavelengths, what would the optical
density requirements be for that worker?
Thomas P. Fuller, ScD, CIH