Blackbody Radiation Calculator
Calculate blackbody radiation spectrum using Planck's law, Wien's displacement law, and Stefan-Boltzmann law
Calculate Blackbody Radiation
Temperature of the blackbody radiator
Emissivity ratio (0-1, where 1 = perfect blackbody)
Specific wavelength for spectral radiance calculation
Blackbody Radiation Results
Total Radiance
Radiance Emittance
Peak Wavelength
Peak Spectral Radiance
Planck's Law: Bλ = (2hc²/λ⁵) × 1/(ehc/λkT - 1)
Wien's Law: λpeak = b/T (b = 2.898×10⁻³ m⋅K)
Stefan-Boltzmann: Total power ∝ εT⁴
Radiation Analysis
Temperature Examples
Key Physics Laws
Planck's Law
Spectral radiance distribution
Wien's Law
Peak wavelength displacement
Stefan-Boltzmann
Total radiated power
Applications
Stellar temperature measurement
Thermal imaging and pyrometry
Lighting and LED design
Satellite thermal analysis
Quantum physics research
Understanding Blackbody Radiation
What is a Blackbody?
A blackbody is an idealized object that absorbs all electromagnetic radiation incident upon it, regardless of frequency or angle of incidence. No electromagnetic radiation passes through it and none is reflected. Because of this property, it is a perfect emitter of thermal radiation.
Quantum Revolution
- •Max Planck's solution to the ultraviolet catastrophe
- •Introduction of energy quantization (E = hν)
- •Foundation of quantum mechanics
- •Nobel Prize in Physics (1918)
Planck's Law
Bλ(λ,T) = (2hc²/λ⁵) × 1/(ehc/λkT - 1)
- Bλ: Spectral radiance (W/m²/sr/μm)
- h: Planck's constant (6.626×10⁻³⁴ J⋅Hz⁻¹)
- c: Speed of light (2.998×10⁸ m/s)
- k: Boltzmann constant (1.381×10⁻²³ J/K)
- λ: Wavelength (m)
- T: Temperature (K)
Wien's Law: λpeak = 2.898×10⁻³/T (m⋅K)
Real-World Examples
The Sun
Surface temperature ~5778K, peak emission in visible spectrum (~500nm)
Incandescent Bulb
Filament ~2500K, peak in near-infrared, inefficient visible light
Human Body
Temperature ~310K, peak emission at ~9.3μm (thermal infrared)