Copper is the most popular material for the windings because of its low resistance and superb ______.

• A. Conductivity
• B. Ductility
• C. Hardness
• D. Magnetic permeability

Answer: (A)

The key factor in winding design is how well a material conducts electricity. Conductivity measures how easily electrons move through a material; higher conductivity means lower resistance for the same size of wire, which reduces energy lost as heat and improves efficiency. Copper is preferred because its electrical conductivity is among the highest of practical metals, giving windings minimal resistive loss as current flows. Ductility, while helpful for drawing wires, isn’t about how readily current travels. Hardness affects mechanical wear rather than electrical performance. Magnetic permeability describes how a material responds to magnetic fields, and copper’s permeability is roughly that of air, not something that enhances winding performance. So the superb property here is conductivity.