The conductivity of aluminum is about ? that of copper.

The conductivity of aluminum is about ? that of copper.

• A. 26%
• B. 50%
• C. 62%
• D. 75%

Answer: (C)

Electrical conductivity compares how easily electrons flow through a material; copper is the reference for high conductivity, while aluminum conducts electricity less well. The ratio is about 60%–62%: aluminum’s conductivity is around 62% of copper’s. This comes from their resistivities: copper is roughly 1.68 μΩ·cm and aluminum about 2.65 μΩ·cm at room temperature, so aluminum’s conductivity is roughly 1/1.58 ≈ 0.63 of copper’s. Therefore, about 62% is the best match.

Electrical conductivity compares how easily electrons flow through a material; copper is the reference for high conductivity, while aluminum conducts electricity less well. The ratio is about 60%–62%: aluminum’s conductivity is around 62% of copper’s. This comes from their resistivities: copper is roughly 1.68 μΩ·cm and aluminum about 2.65 μΩ·cm at room temperature, so aluminum’s conductivity is roughly 1/1.58 ≈ 0.63 of copper’s. Therefore, about 62% is the best match.