Enter blackbody surface area A and absolute temperature T; compute total radiated power P = σ·A·T⁴, showing radiation rising sharply with temperature, for stars, heaters and thermal-radiation estimates.
输入面积 A 与绝对温度 T，求黑体辐射功率。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Stefan-Boltzmann law | P = εσAT⁴ | Stefan-Boltzmann |
| Stefan-Boltzmann constant | σ = 5.670374419×10⁻⁸ W/(m²·K⁴) | CODATA 2018 |
| Emissivity | ε = 1 blackbody, <1 real | Radiation heat transfer |
| Net exchange | P_net = εσA(T⁴ − T_env⁴) | Heat transfer |
| Absolute temperature | Must use kelvin | Thermodynamic scale |
| Fourth-power | Doubling T gives 16× radiation | Radiation scaling |
Constants used on this page and their authoritative sources, for verification and citation
| Constant | Value | Unit | Source |
|---|---|---|---|
| Stefan-Boltzmann constant σ | 5.670374419e-8 | W·m⁻²·K⁻⁴ | CODATA 2018 (derived from exact h, c, k — no uncertainty) |
| Planck constant h | 6.62607015e-34 | J·s | SI defining constant (exact) |
| Boltzmann constant k | 1.380649e-23 | J·K⁻¹ | SI defining constant (exact) |
| Speed of light in vacuum c | 299 792 458 | m·s⁻¹ | SI defining constant (exact) |
Note: σ = 2π⁵k⁴/(15h³c²). Since h, c and k are all exact SI defining constants, σ is likewise exact.