Wien frequency displacement law constant
Physico-chemicalExact
= 5.878 925 757… × 1010 Hz K−1
- Value
- 5.878 925 757… × 1010 Hz K−1
- Standard uncertainty
- exact
- Relative uncertainty
- exact
- Status
- Exact since the 2019 SI redefinition
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
NIST prints this exact value cut to 10 digits. ConstantID recomputes it from the defining constants: 5.878 925 757 646 824 946 606 130 795 31 × 1010…
Use in a calculation
# Wien frequency displacement law constant, CODATA 2022 (NIST)
wien_frequency_displacement_law_constant = 5.8789257576468249466061307953097217e10 # Hz K^-1, exact
# SciPy: scipy.constants.physical_constants['Wien frequency displacement law constant']What it is
The frequency at which a black body's spectrum per unit frequency peaks is b′T. It is not the same point of the spectrum as the wavelength peak, because the two spectra are spread differently.
It is built only from constants that have exact values since 20 May 2019, so it is exact too; CODATA 2018 was the first adjustment to list it that way.
Equations
- Wien's law in frequency
How the value changed, 1998–2022
Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart). Diamonds mark adjustments in which the value was exact.
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 5.878 925 757… × 1010 | exact | exact |
| 2018 | 5.878 925 757… × 1010 | exact | +0.6 σ of 2014 |
| 2014 | 5.878 9238(34) × 1010 | 5.8 × 10−7 | −0.3 σ of 2010 |
| 2010 | 5.878 9254(53) × 1010 | 9.0 × 10−7 | −0.8 σ of 2006 |
| 2006 | 5.878 933(10) × 1010 | 1.7 × 10−6 |
“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).