Question

Copper is abundantly preferred in making wire for electrical use. This is due to-

1. high resistivity of copper
2. low resistivity of copper
3. high ductility of copper
4. low ductility of copper

Answer 1

Correct Answer - Option 2 : low resistivity of copper

The correct answer is option 2) i.e. low resistivity of copper

CONCEPT:​

• The resistivity (ρ) of a material is defined as the resistance offered by a material of unit cross-sectional area and unit length. 
  • Resistivity is an intrinsic property i.e. it is the same for a given type of material.
• Conductivity (σ) is the reciprocal of electrical resistivity.

\(\Rightarrow \sigma = \frac{1}{ρ}\)

​EXPLANATION:

• The material used for electrical purposes should be a good conductor of electricity i.e. it must have high conductivity.
• As conductivity is the reciprocal of resistivity, high conductivity implies low resistivity. 
• Thus, the low resistivity of copper is the reason why it is preferred for making electrical wires.

 

• Ductility is the physical property of a material that defines its ability to be hammered or stretched into thin wires without breaking. A ductile substance can be easily drawn into a wire.
• Thus, ductility can be considered while making electrical wires. However, there are other metals that are more ductile than copper (ex: gold).
• In the making of electrical wires, the conductivity of the material dominates over its ductility.