🪐intro to astronomy review

Wien’s law

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Wien's law states that the wavelength at which a blackbody radiates most intensely is inversely proportional to its temperature. This means hotter objects emit radiation at shorter wavelengths.

AP course connection

Topic 5.2: 5.2 The Electromagnetic Spectrum

Unit 5

5 Must Know Facts For Your Next Test

  1. Wien's law can be mathematically expressed as λ_max = b/T, where λ_max is the peak wavelength, T is the absolute temperature in Kelvin, and b is Wien's constant (approximately 2.897 x 10^-3 m·K).
  2. The law helps astronomers determine the surface temperatures of stars by examining their emitted spectra.
  3. As an object's temperature increases, the peak wavelength of emitted radiation shifts toward the blue end of the spectrum.
  4. Wien's law applies to idealized objects known as blackbodies, which are perfect absorbers and emitters of radiation.
  5. This principle is vital in understanding various astronomical phenomena and interpreting data from telescopes observing different wavelengths.

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