Rate of heat flow
This article needs additional citations for verification. (August 2008) (Learn how and when to remove this template message)
where is the rate of heat flow, is the thermal conductivity factor, is the surface area, is the change in temperature, and is the thickness of the material ( is called the temperature gradient and is always negative because the heat always flows from the higher temperature to the lower).
Assume there are two systems with the same mass and specific heat. System A has an average temperature of 500 kelvins, and system B has an average temperature of 400 K. If 30 seconds after the systems are put in contact they both reach 450 K, then the average rate of heat flow is
- 50 J/(30 s) ≈ 1.67 W.
(note: specific heat capacities = 1 J/(kg K) and masses = 1 kg).
|This physics-related article is a stub. You can help Wikipedia by expanding it.|