Lei de Stefan-Boltzmann

Last updated: 2026-08-24

Lei de Stefan-Boltzmann — Calcule a potência radiada por um corpo negro.
Inputs
Result
Enter values and press Calculate

How to use it

  1. Temperature T = 500 K, area A = 2.5 m², emissivity ε = 0.85
  2. Calculate T⁴ = 500⁴ = 6.25×10¹â°
  3. Multiply: σ × ε × A × T⁴
  4. P = 5.670374×10⁻⁸ × 0.85 × 2.5 × 6.25×10¹â° ≈ 7533.16 W

Common mistakes

  • ⚠️ Using Celsius instead of Kelvin (must be absolute temperature)
  • ⚠️ Forgetting emissivity factor (assumes blackbody)
  • ⚠️ Wrong power of temperature (must be T⁴)

Worked example

Find radiated power from a 2.5 m² surface at 500 K with emissivity 0.85.

The radiated power {power} W is emitted according to the Stefan-Boltzmann law.

Input guide

FieldTypical range
areaSurface area: 0.001 to 1000 m²
emissivityEmissivity: 0.01 to 1.0
TTemperature: 100 to 5000 K