Wilhelm Wien

Physicist — Wilhelm Wien (1864–1928) was a German physicist, a student of Hermann von Helmholtz and a central figure in the study of thermal radiation. He worked at the Physikalisch-Technische Reichsanstalt in Berlin and later taught at Würzburg and Munich. In 1893 he formulated the displacement law that bears his name, according to which the wavelength at which a black body emits maximum energy is inversely proportional to its absolute temperature. He also proposed a radiation distribution law (Wien approximation) valid at high frequencies, which represented a crucial step towards Planck’s full law and the birth of quantum physics. For these discoveries concerning black-body radiation he received the Nobel Prize in Physics in 1911.

Trivia

His displacement law explains why a body, as it heats up, changes colour from red to blue-white, and allows the surface temperature of stars to be estimated from their colour.

Theories and contributions

• Wien’s displacement law — The wavelength of maximum emission is inversely proportional to the temperature: $\lambda_{max}\,T = b$, with $b\approx 2.898\times10^{-3}\,\mathrm{m\cdot K}$.
• Wien’s law (approximation) — Spectral distribution of the black body valid at high frequencies, a forerunner of Planck’s law.

Appears in chapters

08b 21

Linked atoms

2 linked atoms.

08b Termologia

• The greenhouse effect

21 Introduzione alla meccanica quantistica

• What is a black body?