Based on Max Plank’s postulates of electromagnetic radiation, Plank explained the black body radiations.
✔ Matter can either absorb or release energy only of some characteristic frequencies and not all.
✔ Energy absorption or emission hence cannot be continuous but only discrete.
✔ The energy absorbed or emitted = E = hν: where,
h is a Planks constant= 6.626 ×10-34 Js and ν is the frequency of radiation.
✔ Total energy of the radiation is emitted is an integral multiple of this basic unit. E= nhν
✔ Intensity function; ρ(λ,T)
\(\begin{array}{l}=frac{2h{{c}^{2}}}{{{lambda }^{5}}}times frac{1}{frac{hc}{{{e}^{lambda KT}}}-1}\end{array} \)
When, λ → 0,
\(\begin{array}{l}frac{hc}{{{e}^{lambda KT}}}=frac{hc}{lambda KT}+1\end{array} \)
, so that,
=
\(\begin{array}{l}=,frac{2h{{c}^{2}}}{{{lambda }^{5}}}times frac{lambda KT}{hc},=frac{2cKT}{{{lambda }^{4}}}\end{array} \)
= Reyleigh -Jeans formula
So, Plank’s, relation is valid even at low wavelength and does not predict ‘ultraviolet catastrophe’.
The particle (quantum) model proposed by Max Plank explains black body radiation,.
