Electrical vs Thermal Conductivity
Thermal conductivity and electrical conductivity are two very important physical properties of matter. The thermal conductivity of a material describes how fast the material can conduct thermal energy. The electrical conductivity of a material describes the electrical current that will occur due to a given potential difference. Both of these properties are well characterized and have a vast amount of applications in fields such as power generation and transmission, electrical engineering, electronics, thermodynamics and heat and many other fields. In this article, we are going to discuss what thermal conductivity and electrical conductivity are, their definitions, similarities between thermal conductivity and electrical conductivity, their applications and finally the difference between thermal conductivity and electrical conductivity.
The resistance of a component depends on various parameters. The length of the conductor, the area of the conductor, and the material of the conductor are to name some. The conductivity of a material can be defined as the conductance of a block having unit dimensions made out of the material. The conductivity of a material is the inverse of the resistivity. Conductivity is usually denoted by the Greek letter σ. The SI unit of conductivity is siemens per meter. It must be noted that conductivity is specifically a property of the material at a given temperature. The conductivity is also known as specific conductance. The conductance of a component is equal to the conductivity of the material multiplied by area of the material divided by the length of the material. When conducting electricity, the electrons inside the material move from a higher potential to a lower potential. The conductance of a component can also be defined as the current generated per unit voltage difference. The conductance is a property of the object whereas electrical conductivity is a property of the material.
Thermal conductivity is the ability of a material to conduct thermal energy. The thermal conductivity is a property of the material. The thermal conductance is a property of the object. The most important law behind thermal conductivity is the heat flow equation. This equation states that the rate of heat flow through a given object is proportional to the area of cross section of the object and the temperature gradient. In a mathematical form, this can be written as dH/dt = kA(∆T)/l, where k is the thermal conductivity, A is the cross area, ∆T is the temperature difference between the two ends and l is the length of the object. ∆T/l can be termed as temperature gradient. The thermal conductivity is measured in watt per kelvin per meter.
What is the difference between Thermal Conductivity and Electrical Conductivity?
• In thermal conduction, the heat is transferred by the oscillation of atoms inside the material. In electrical conduction, the electrons themselves move in order to create the current.
• Most of the thermal conductors are good electrical conductors.Both thermal conductivity and the electrical conductivity depend on the material.
• In thermal conductivity, energy is transferred but in electrical conductivity electrons are transferred.