Thermal conductivity

Definition

Thermal conductivity is a material's ability to conduct heat. It quantifies the rate at which heat energy passes through a material given a temperature gradient.

5 Must Know Facts For Your Next Test

1. Thermal conductivity is denoted by the symbol $k$ or $\lambda$.
2. The SI unit of thermal conductivity is watts per meter-kelvin (W/m·K).
3. Materials with high thermal conductivity, like metals, are good conductors of heat.
4. The formula for heat transfer through conduction is $Q = kA \frac{dT}{dx}$ where $Q$ is the heat transferred, $A$ is the area, and $\frac{dT}{dx}$ is the temperature gradient.
5. Thermal conductivity depends on factors like material composition, temperature, and phase.

Review Questions

• What does thermal conductivity measure?
• Write down the formula for heat transfer through conduction using thermal conductivity and explain each term.
• Why do metals generally have higher thermal conductivity than non-metals?

Related terms

Conduction:

The process of heat transfer through a material without any motion of the material as a whole.

Heat Flux: The rate of heat energy transfer through a given surface per unit time.

Temperature Gradient:

The rate of change in temperature with respect to distance within a substance.