Which radioactive material is commonly used in radiography?

Cobalt, particularly cobalt-60, is commonly used in radiography due to its properties that make it effective for imaging purposes. Cobalt-60 emits gamma radiation, which can penetrate materials, allowing for clear imaging of internal structures in metals and other dense materials. This quality is essential in non-destructive testing (NDT) applications, where the integrity of materials needs to be examined without causing any damage.

In addition, cobalt-60 is relatively convenient to handle and produces a consistent output of radiation, making it a preferred choice in industrial radiography. Its usage is well-established, and it adheres to safety regulations that make it suitable for environments where radiography is performed.

While other materials like radon, uranium, and cesium have various applications in different areas of science and medicine, they do not have the same level of acceptance or widespread use in radiography as cobalt-60 does. Radon is primarily associated with health risks and environmental studies, uranium is mainly known for its use in nuclear energy and weapons, and cesium is often used in medical applications rather than in industrial radiography.