Which method assures adequate rinsing when using fluorescent water-washable penetrant?

Which method assures adequate rinsing when using fluorescent water-washable penetrant?

• A. Rinsing under black light
• B. Rinsing under white light
• C. Rinsing with solvent
• D. Rinsing for 5 minutes

Answer: (A)

The crucial idea is that rinsing adequacy for fluorescent water-washable penetrant is verified by using ultraviolet (black) light. Fluorescent penetrants glow under UV, so after rinsing you inspect the surface with a black light. If any fluorescent residue remains, it will light up, signaling that more rinsing is needed. White light won’t reveal this glow, so it can’t confirm rinsing completeness. Rinsing with solvent isn’t appropriate for water-washable penetrants, and timing alone (like a fixed duration) doesn’t reliably indicate thorough rinsing due to variations in surface texture and penetrant amount.

The crucial idea is that rinsing adequacy for fluorescent water-washable penetrant is verified by using ultraviolet (black) light. Fluorescent penetrants glow under UV, so after rinsing you inspect the surface with a black light. If any fluorescent residue remains, it will light up, signaling that more rinsing is needed. White light won’t reveal this glow, so it can’t confirm rinsing completeness. Rinsing with solvent isn’t appropriate for water-washable penetrants, and timing alone (like a fixed duration) doesn’t reliably indicate thorough rinsing due to variations in surface texture and penetrant amount.