Wien Peak Wavelength Calculator Formula
Understand the math behind the wien peak wavelength calculator. Each variable explained with a worked example.
Formulas Used
Peak Wavelength
wavelength_m = 2.8978e-3 / temperaturePeak Wavelength (nm)
wavelength_nm = 2.8978e-3 / temperature * 1e9Peak Wavelength (µm)
wavelength_um = 2.8978e-3 / temperature * 1e6Variables
| Variable | Description | Default |
|---|---|---|
temperature | Temperature(K) | 5778 |
How It Works
Wien's Displacement Law
lambda_max = b / T
where b = 2.8978 × 10⁻³ m·K (Wien's displacement constant).
Hotter objects peak at shorter wavelengths. The Sun (5778 K) peaks at about 502 nm (green-yellow visible light). A human body (310 K) peaks at about 9.35 µm (infrared).
Worked Example
The Sun at T = 5778 K.
- 01lambda_max = 2.8978e-3 / 5778
- 02= 5.016e-7 m = 501.6 nm
- 03This is in the green part of the visible spectrum.
Frequently Asked Questions
Why does the Sun appear white/yellow rather than green?
The Sun emits broadly across the visible spectrum. Our eyes integrate all wavelengths, perceiving white light. The atmosphere scatters blue, shifting the perceived colour toward yellow.
What temperature peaks in visible light?
About 4000-7000 K. Below this, the peak shifts to infrared (we see red). Above, it shifts to ultraviolet (we see blue-white).
Does Wien's law apply to non-blackbodies?
It is exact only for ideal blackbodies. Real objects may have emission lines or absorption features altering the spectrum, but the overall peak still roughly follows Wien's law.
Ready to run the numbers?
Open Wien Peak Wavelength Calculator