Which statement correctly describes how dye penetrant inspection works?

Which statement correctly describes how dye penetrant inspection works?

• A. It uses magnetic particles to indicate cracks
• B. It uses dye penetrant and a developer to reveal cracks
• C. It uses radiography to reveal cracks
• D. It uses ultrasonic waves to reveal cracks

Answer: (B)

Dye penetrant inspection works by letting a liquid dye seep into any surface-breaking cracks, then drawing it out with a developer so the flaw becomes visible. After cleaning the surface, the penetrant is applied and given time to enter cracks. Excess penetrant is removed, and a developer is applied; the developer pulls the dye from the cracks to the surface, creating a visible line or glow under the right light. This is exactly what the statement describes: using dye penetrant and a developer to reveal cracks. Other methods rely on different principles—magnetic particles for magnetic particle inspection, X-ray or gamma rays for radiography, and sound waves for ultrasonic testing—so they don’t describe how dye penetrant inspection works.

Dye penetrant inspection works by letting a liquid dye seep into any surface-breaking cracks, then drawing it out with a developer so the flaw becomes visible. After cleaning the surface, the penetrant is applied and given time to enter cracks. Excess penetrant is removed, and a developer is applied; the developer pulls the dye from the cracks to the surface, creating a visible line or glow under the right light. This is exactly what the statement describes: using dye penetrant and a developer to reveal cracks. Other methods rely on different principles—magnetic particles for magnetic particle inspection, X-ray or gamma rays for radiography, and sound waves for ultrasonic testing—so they don’t describe how dye penetrant inspection works.