Rate of conductive heat transfer

Definition

The rate of conductive heat transfer is the amount of thermal energy transferred per unit time through a material due to temperature differences. It depends on the material's thermal conductivity, cross-sectional area, temperature gradient, and thickness.

5 Must Know Facts For Your Next Test

1. The formula for the rate of conductive heat transfer is given by Fourier's Law: $Q = \frac{dQ}{dt} = -kA\frac{dT}{dx}$.
2. Thermal conductivity ($k$) is a property that measures a material's ability to conduct heat.
3. The negative sign in Fourier's Law indicates that heat flows from higher to lower temperatures.
4. Units for the rate of conductive heat transfer are Watts (W), which is equivalent to Joules per second (J/s).
5. Materials with high thermal conductivity, like metals, transfer heat more quickly than those with low thermal conductivity, like insulators.

Review Questions

• What factors affect the rate of conductive heat transfer according to Fourier's Law?
• Explain why there is a negative sign in Fourier's Law equation for conductive heat transfer.
• How does the thermal conductivity of a material influence its ability to conduct heat?

Related terms

Thermal Conductivity: A property of a material that indicates its ability to conduct heat. Higher values mean better conduction.

Temperature Gradient: The rate of temperature change with respect to distance within a material.

Insulator: A material with low thermal conductivity that resists the flow of heat.