Stefan-Boltzmann Law
Power radiated by a body due to its temperature. The emissivity ε covers real (gray) surfaces; setting ε = 1 gives the ideal blackbody form P = σAT⁴. This is the comprehensive, general form of the law.
Variables
Derivation
Derived from Planck blackbody radiation law.
Your notes
Constants in this formula
Other thermodynamics formulas with the same quantities
- Work (Isothermal Process) (First Law) shares Temperature
- Internal Energy (Ideal Gas) (First Law) shares Temperature
- Entropy Change (Second Law) shares Temperature
- Ideal Gas Law (Kinetic Theory) shares Temperature
- Ideal Gas Law (Molecular) (Kinetic Theory) shares Temperature
- Average Kinetic Energy (Gas) (Kinetic Theory) shares Temperature
Where this formula is listed
- Thermodynamics formulas, under Heat & Temperature, alongside Heat Capacity, Latent Heat, Linear Thermal Expansion, Volume Thermal Expansion and Thermal Resistance.
- In the thermodynamics list it comes after Heat Conduction and before Thermal Resistance.
- Thermodynamics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Stefan-Boltzmann Law formula?
Stefan-Boltzmann Law is written P = εσAT⁴. Power radiated by a body due to its temperature. The emissivity ε covers real (gray) surfaces; setting ε = 1 gives the ideal blackbody form P = σAT⁴. This is the comprehensive, general form of the law. It belongs to Thermodynamics, under Heat & Temperature.
What are the units in P = εσAT⁴?
In SI units, P is radiated power, measured in kg·m²/s³; ε is emissivity (dimensionless); σ is stefan-boltzmann constant, measured in kg/(s³·K⁴); A is surface area, measured in m²; T is temperature, measured in K.
How is the Stefan-Boltzmann Law formula derived?
Derived from Planck blackbody radiation law. The result is P = εσAT⁴.