Texas Industrial Radiography Gamma Practice Test

What primarily determines the penetrating ability of Gamma or X-Radiation?

1. Distance from the source

2. Energy level, Kev or Mev

3. Curie Strength

4. Specific Activity

The correct answer is: Energy level, Kev or Mev

The penetrating ability of gamma or X-radiation is primarily determined by the energy level of the radiation, measured in kilo-electron volts (Kev) or mega-electron volts (Mev). Higher energy radiation has a greater ability to penetrate materials, allowing it to pass through more dense substances such as metals and organic tissues. This energy correlates with the photons' momentum and their ability to interact with matter. In contrast, other factors such as distance from the source, curie strength, and specific activity are related to the intensity and behavior of radiation but do not intrinsically determine the inherent penetrating power of the radiation itself. For instance, while increasing the distance from the source can reduce exposure due to the inverse square law, it doesn't change the energy of the radiation emitted. Similarly, curie strength pertains to the quantity of radioactive material and its half-life, and specific activity is a measure of radioactivity per unit mass, both of which influence dose rate but not the fundamental penetrating quality of the emitted radiation.