"Also note that the surface of a sealed box will be at the same temperature as its contents, e.g. the temperature of a die, and the wrapping of a tightly wrapped die, will be the same. It's called the law of conservation of energy.... "
No, this is not so.
In a steady-state situation with a heat source (power source) somewhere inside a system (box, case, etc), the temperature at the source will be higher than the temperature further out. This is implied by the usual heat flow equations.
For example, consider a heat-producing chip glued to the wall of a large house, the house acting as the case. Do you think the temperature of the roof of the house, or the walls, or the basement floor, is "at the same temperature as it contents"?
Granted, a chip case is much smaller than a house. But the same logic applies. Heat flow equations determine the case temperature, not simplistic reasoning that the law of conservation of energy requires the temperatures to be the same...which it doesn't.
--Tim May |
