property>first radiation constant

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 / (ε^c₂/λT - 1)