Wien’s Law Calculator
Calculate blackbody peak wavelength from temperature.
Wien’s Displacement Law
λmax = b/T, with b ≈ 2.897771955 × 10⁻³ m·K.
What Is Wien’s Displacement Law?
Wien’s law links the absolute temperature of an ideal blackbody to the wavelength at which its emission spectrum reaches maximum intensity. Hotter objects peak at shorter wavelengths, while cooler objects peak farther into the infrared.
Example Calculation
For a blackbody at 5,800 K, λmax = 2.897771955 × 10⁻³ / 5,800 ≈ 5.00 × 10⁻⁷ m, or about 500 nm, near the visible part of the spectrum.
Factors and Interpretation
Peak wavelength is inversely proportional to temperature. Doubling absolute temperature halves the peak wavelength. Real objects may not behave as perfect blackbodies, but Wien’s law remains a useful first approximation for stars, hot surfaces and thermal emitters.
Frequently Asked Questions
Why must temperature be in kelvin?
The law uses absolute temperature, so kelvin is required.
Does the peak wavelength contain all emitted energy?
No. A blackbody emits over a broad spectrum; λmax marks only the strongest wavelength region.
How is Wien’s law different from Stefan-Boltzmann law?
Wien’s law predicts peak wavelength, while Stefan-Boltzmann law predicts total emitted power.
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Formula and Practical Limits
Wien’s displacement law relates a blackbody’s absolute temperature to its peak wavelength. Real objects may not behave as perfect blackbodies, and the peak depends on the spectral representation used.