When was the Zyglo system of fluorescent penetrant inspection introduced?

• A. in 1925 by Magnaflux
• B. in 1935 by Magnaflux
• C. in 1950 by Magnaflux
• D. in 1942 by Magnaflux

Answer: (D)

The question tests knowledge of when Magnaflux’s Zyglo fluorescent penetrant system first became available. Zyglo marked a shift to fluorescent penetrants, using a dye that glows under UV light to reveal cracks with bright, high-contrast fluorescence. This system was introduced in 1942, during a period when reliable nondestructive testing for aircraft and other critical components was essential. The higher sensitivity of fluorescent penetrants under ultraviolet illumination made it easier to detect smaller flaws than older visible-color penetrants, which is why Zyglo became a landmark in LPI. The earlier dates don’t align with the known rollout of this brand, and 1950 would be after the established introduction of Zyglo.