Electrical Conductivity

Definition

Electrical conductivity is a measure of a material's ability to conduct electric current, often represented by the symbol $$ ho$$ (sigma). It is influenced by factors such as temperature, the presence of impurities, and the structure of the material. Understanding electrical conductivity is crucial for exploring properties of materials, energy transfer, and electronic applications.

5 Must Know Facts For Your Next Test

1. Electrical conductivity is significantly influenced by temperature; generally, as temperature increases, the conductivity of metals decreases while that of semiconductors increases.
2. In crystalline solids, the symmetry operations can affect how charge carriers move, thus impacting the overall conductivity of the material.
3. The free electron model explains that in metals, conduction occurs due to the movement of free electrons, leading to higher electrical conductivity.
4. Defects in materials such as point defects and grain boundaries can impede the flow of charge carriers, reducing electrical conductivity.
5. Carbon nanotubes and graphene are known for their exceptional electrical conductivity due to their unique structures and electron mobility.

Review Questions

• How does the free electron model explain the high electrical conductivity observed in metals?
  • The free electron model suggests that in metals, there are numerous free electrons that can move freely throughout the lattice structure. This movement allows for easy conduction of electric current when an electric field is applied. The presence of these free electrons is what makes metals good conductors compared to insulators, where such free movement is restricted.
• Discuss how planar defects and grain boundaries can affect the electrical conductivity of a material.
  • Planar defects and grain boundaries can significantly hinder the movement of charge carriers within a material. When an electric field is applied, these imperfections create scattering centers that impede electron flow. As a result, materials with higher concentrations of such defects typically exhibit lower electrical conductivity compared to their perfect crystalline counterparts.
• Evaluate the implications of electrical conductivity variations in semiconductors concerning their applications in modern electronics.
  • The variations in electrical conductivity in semiconductors are pivotal for their function in modern electronics, such as transistors and diodes. By manipulating factors like doping concentration and temperature, semiconductors can transition from insulators to conductors, enabling precise control over current flow. This characteristic allows for the development of complex electronic circuits essential for computing and communication technologies.

Related terms

Resistivity: Resistivity is the inverse of conductivity and measures how strongly a material opposes the flow of electric current, typically represented by the symbol $$\rho$$.

Semiconductors:

Semiconductors are materials that have electrical conductivity between that of conductors and insulators, with their conductivity being highly sensitive to temperature and doping.

Superconductivity: Superconductivity is a phenomenon where a material exhibits zero electrical resistance and expels magnetic fields when cooled below a certain critical temperature.