Red Seal Electrician Practice
Wiring and componentsQuestion 461 of 1506

Why does heat from the soldering iron make flux necessary even on freshly cleaned copper?

  1. Heat speeds up surface oxidation
  2. Heat makes copper non-conductive
  3. Heat makes the solder harder
  4. Heat removes the copper oxide
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Correct answer: Heat speeds up surface oxidation

Oxidation is hastened by heat.

Source: Electrical Fundamentals Competency (Industry Training Authority of BC), 10.1: Solder Bonding

Practice wiring and components

Questions last reviewed: 18 October 2026