A weld inspector uses ultraviolet light when performing which type of inspection?

The use of ultraviolet light during inspections is specifically associated with fluorescent penetrant testing. In this method, a fluorescent dye is applied to the surface of a material. When exposed to ultraviolet light, the dye fluoresces, making it easier to detect surface defects such as cracks and porosity. The glow from the dye against the dark background created by the ultraviolet light enhances visibility, allowing inspectors to identify flaws that might otherwise be missed under normal lighting conditions.

In contrast, dye penetrant testing may involve visible dyes and does not require ultraviolet light to detect flaws, while ultrasonic and radiographic testing utilize sound waves and x-rays respectively, neither of which depend on ultraviolet illumination for flaw detection. The distinctive nature of fluorescent penetrant testing relies on the combination of the fluorescent dye and the specific lighting conditions provided by ultraviolet light, making it the appropriate choice for this type of inspection.