first radiation constant
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What is the First Radiation Constant?
The first radiation constant, c1, is used in the Planck's law. It has the SI units of watts square metres. It is given by the equation:
c1 = 2π.hc2
where h is the Planck constant and c is the speed of light. Its value is 3.741771x10-16 Wm2.
Planck's law gives the radiation intensity emitted by a black body for a given frequency and temperature. It has the form:
u = c1.λ-5 / (εc2/λT - 1)