Equations
Power radiated by a real surface
Thermodynamics · id stefan_boltzmann_emissivity
P = \varepsilon \sigma A T^4
| Symbol | Quantity | Unit | Meaning | Usual range |
|---|---|---|---|---|
P | radiated power | W | Thermal radiation emitted | 0 to 1e+30 |
eps | emissivity | dimensionless | How close the surface is to a black body | 0.01 to 1 |
sigma | Stefan-Boltzmann constant | W/(m^2*K^4) | Radiation constant | |
A | surface area | m^2 | Radiating surface area | 1e-06 to 1e+20 |
T | temperature | K | Absolute temperature of the surface | 1 to 100000 |
Assumptions
- Gray body: emissivity the same at all wavelengths
Valid when
- No extra conditions.
Found by
Questions with these words retrieve this equation: radiation, emissivity, thermal radiation, glowing, heat loss, infrared.
Source
OpenStax University Physics Volume 2, Chapter 1 (reference; entry written by the project). License: MIT. Entry confidence: 0.98.