Question

Write an expression for the Planck's law of radiation?

Answer 1

Planck's law of radiation is given as follows:

$$B(\nu, T) = \frac{ 2 h \nu^3}{c^2} \frac{1}{e^\frac{h\nu}{k_\mathrm B T} - 1}$$

where $B(\nu, T)$ is the spectral radiance of a body for frequency $\nu$  at absolute temperature $T$, $k_B$ is the Boltzmann constant, $h$ is the Planck constant, and $c$ is the speed of light in the medium.