If a fluorescent dye penetrant and ultra-violet light are used for leak detection on a heat exchanger, what would be the indication of a confirmed leak?

Correct Answer: Option A — A bright green glow at the site of leakage.

Fluorescent dye penetrants are specifically formulated to react under ultra-violet (black) light by emitting a high-visibility green glow. This contrast allows maintenance personnel to detect minute leaks in heat exchanger plates or welds that would otherwise remain invisible to the naked eye during routine inspections.