Technician exam question T7D09
Subelement T7, PRACTICAL CIRCUITS· Group T7D
What is the characteristic appearance of a cold tin-lead solder joint?
- A.Dark black spots
- B.A bright or shiny surface
- C.A rough or lumpy surface (correct answer)
- D.A greenish tinge
WhyA cold tin-lead solder joint characteristically has a rough or lumpy surface. A cold solder joint forms when the solder doesn't fully melt and bond with the surfaces being joined, leaving it with a dull, rough, or lumpy texture instead of the smooth, shiny finish of a good joint, answer C. Dark spots (A) and a greenish tinge (D) suggest contamination or corrosion rather than a cold joint specifically, and a bright, shiny surface (B) actually describes what a properly made joint looks like.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2026-2030 NCVEC Element 2 pool (public domain); the explanation above is original writing, see our methodology.
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