Besides low resistance, what other property of copper contributes to its use in windings?

• A. High conductivity
• B. Low density
• C. High melting point
• D. Magnetic permeability

Answer: (A)

High electrical conductivity is the key property. Copper’s ability to conduct electricity exceptionally well means current can flow with minimal energy lost as heat, so windings carry large currents efficiently and stay cooler. This complements its low resistance to keep voltage drops small and minimize I²R losses, which is crucial for efficient transformers and motors. The other options aren’t as relevant: low density affects weight more than electrical performance; a high melting point helps with heat tolerance but isn’t the main reason windings work well; magnetic permeability in copper is not high (it’s about the same as free space), so it doesn’t contribute to winding behavior.