Which of the following factors MOST affects the penetrating power of an x-ray?

The penetrating power of an x-ray is primarily influenced by the kilovoltage (kV) setting used during the exposure. Higher kilovoltage increases the energy of the x-ray photons produced, which in turn enhances their ability to penetrate through various tissues. This results in images that show more detail and contrast, as the x-rays can effectively pass through denser materials such as bone and highlight differences in structure within the tissue.

When kilovoltage is raised, the x-ray beam becomes more powerful, facilitating better penetration of the beam through the patient, and improving diagnostic quality. Conversely, lower kilovoltage results in a lower energy beam that may not penetrate adequately, leading to images that lack detail or are overly dark due to insufficient exposure of the film.

While exposure time, milliamperage, and the length of the PID (Position Indicating Device) do have roles in the overall quality and efficiency of an x-ray procedure, they do not have as direct an effect on the beam's penetration power as kilovoltage. Exposure time determines how long the film is exposed to radiation, while milliamperage affects the quantity of x-rays produced but not their energy. The length of the PID can influence the divergence of the x-ray beam but