Wien’s constant

You can also use Wien’s law to find the surface temperature of an object based on its peak wavelength. For example, the following set of equations shows how to calculate the temperature of a star with a peak wavelength of about 400 nm (the violet end of the visible range):

λ_max = b / T
400 nm = 2.89777 ⋅ 10^-3 m ⋅ K / T
400 nm = 0.0028977 m ⋅ K / T
400 nm = 2,897,700 nm ⋅ K / T
T = 2,897,700 nm ⋅ K / 400 nm
T = 7,244.25 K

The surface temperature of a star with a peak wavelength of 400 nm is about 7,244.25 K, which means the star is hotter than our sun. This points to another important aspect of Wien’s law: As a black body grows hotter, the wavelength of its peak energy output grows shorter, placing it higher on the electromagnetic spectrum.

See also: solar constant, passive solar, solar cooling, radiant energy, kinetic energy, heat and potential energy.