Stefan-Boltzmann Law

Snapshot 1: domestic fireplace radiation

Snapshot 2: industrial smelter radiation

Snapshot 3: sun-like stellar radiation

This Demonstration plots the radiated heat in or from a hot body having a given emissivity, , as a function of its temperature and that of its surroundings, both entered either in °C or °K. This heat output is calculated with the Stefan-Boltzmann law, , where is the emissivity, is the Stefan-Boltzmann constant, is the area in (equal to 1 in this Demonstration), is the radiating body temperature, and is the ambient temperature, both in °K. The upper graphic is a schematic visual representation of the selected emissivity (not to scale).

Reference: C. J. Geankoplis, Transport Processes and Unit Operations, ed., Boston: Allyn and Bacon, 1983.