Which statement concerning liquid penetrant testing is correct?

Which statement concerning liquid penetrant testing is correct?

• A. Visible indications are seen under ordinary light
• B. Fluorescent indications will be seen when exposed to black light
• C. Indications are only visible under magnification
• D. Penetrant testing does not produce indications

Answer: (B)

In liquid penetrant testing, there are two types of indications: visible and fluorescent. The fluorescent type uses a dye that glows under ultraviolet light, so you see the indications when exposed to UV (black light). That makes the statement about fluorescent indications appearing with black light correct. Under ordinary white light, those fluorescent indications won’t be visible, which is why other options—such as indications always being visible under normal light or only appearing with magnification—aren’t accurate. Also, penetrant testing does produce indications when flaws are present, so the statement that it does not produce indications is false.

In liquid penetrant testing, there are two types of indications: visible and fluorescent. The fluorescent type uses a dye that glows under ultraviolet light, so you see the indications when exposed to UV (black light). That makes the statement about fluorescent indications appearing with black light correct. Under ordinary white light, those fluorescent indications won’t be visible, which is why other options—such as indications always being visible under normal light or only appearing with magnification—aren’t accurate. Also, penetrant testing does produce indications when flaws are present, so the statement that it does not produce indications is false.