Electrical Conductivity - Specific Conductance
What is Electrical Conductivity
Electrical conductivity, denoted by the letter (σ) “sigma” or (κ) “kappa”, is a material property that describes its ability to conduct electric current. It is a measure of how easily an electric current can flow through a material.
The electrical conductivity of a material is determined by the number of free electrons in the material and their mobility. Materials that have a high number of free electrons and allow them to move easily have high electrical conductivity, while materials with few free electrons have low electrical conductivity.
Electrical conductivity and conductance are closely related properties, however, they are not the same thing. Conductivity is an intrinsic property of the material itself, whereas conductance is a property of a particular electrical component and depends on the dimensions of that component.
Formula & Units
The electrical conductivity formula is given by:
Where:
- σ is the electrical conductivity
- ρ is the electrical resistivity
The SI unit of electrical conductivity is siemens per meter (S/m).
Factors Affecting Electrical Conductivity
The electrical conductivity of a material can be affected by several factors, including:
- Temperature: Generally, as the temperature of a material increases, its electrical conductivity decreases. This is because, at higher temperatures, the atoms and ions in a material vibrate more rapidly, which can interfere with the movement of electrons or ions through the material.
- Composition: The type and amount of impurities, dopants, or alloys in a material can significantly affect its conductivity.
- Atomic Structure: The arrangement of atoms in a material can affect its electrical conductivity. For example, materials with a regular, repeating structure (such as crystals) tend to be good conductors, while those with a disordered structure (such as glasses) tend to be poor conductors.
- Physical Factors: Physical factors such as pressure, strain, and deformation can affect the arrangement of atoms in a material, which can influence its electrical conductivity.
- Magnetic fields: The electrical conductivity of some materials, such as metals and semiconductors, can be affected by the presence of magnetic fields due to the interaction between charge carriers and magnetic fields.
Applications of Electrical Conductivity
Electrical conductivity is a critical property that has many applications in several fields. Some of the main applications of electrical conductivity are:
- Electronics: Electrical conductivity is essential in the production of electronic components such as wires, connectors, and printed circuit boards.
- Power transmission: High electrical conductivity is necessary for power transmission and distribution systems, such as overhead power lines and underground cables, to minimize energy loss.
- Heating: Electrical conductivity is utilized in heating elements for cooking appliances, water heaters, and industrial furnaces.
- Sensing: Electrical conductivity is used in sensors and detectors for various applications, including temperature sensing, gas sensing, and strain sensing.
- Corrosion protection: Electrical conductivity is used in cathodic protection systems to prevent corrosion of metal structures such as pipelines, tanks, and bridges.
- Medical applications: Electrical conductivity is used in medical applications, such as in electroencephalography (EEG) and electrocardiography (ECG), to monitor brain and heart activity, respectively.
Understanding the importance and applications of electrical conductivity can help in the development and optimization of new materials and devices for various fields.
Electrical Conductivity Summary | ||
|---|---|---|
| Definition | The measure of how easily an electric current can flow through a material | |
| Symbol | σ or κ | |
| Formula | ||
| Units | SI unit (S/m) | |
Frequently Asked Questions
- What does electrical conductivity mean?
- ELectrical conductivity is a measure of how easily an electricl current can flow through a material.
- Is electrical conductivity physical or chemical?
- ELectrical conductivity is a physical property, as the chemical properties of a material remain the same while it’s conducting electricity. For example a copper wire, is still copper while it’s conducting electricity.
- What is the relation between electrical conductivity and resistivity?
- Electrical conductivity is the inverse of electrical resistivity.
- What is the best metal for electrical conductivity?
- Silver is the best conducter of electricity in pure metals.