1. Wien's Displacement Law:
* This law states that the peak wavelength of blackbody radiation is inversely proportional to the temperature of the object.
* As wavelength increases beyond the peak, the temperature required to emit radiation at that wavelength becomes higher.
* This means that fewer photons are emitted at longer wavelengths, leading to a decrease in spectral radiance.
2. Energy Distribution:
* At shorter wavelengths (before the peak), most of the energy emitted by the blackbody is concentrated in the form of high-energy photons.
* At longer wavelengths (after the peak), the energy is distributed among a larger number of lower-energy photons.
* This shift in energy distribution results in a lower spectral radiance at longer wavelengths.
3. Quantum Mechanics:
* Planck's law, which describes the shape of the Planck curve, is based on quantum mechanics.
* According to quantum mechanics, the energy of photons is quantized, meaning they can only exist in discrete energy levels.
* As wavelength increases, the energy of photons decreases, leading to a decrease in the number of photons emitted at longer wavelengths.
4. Boltzmann Distribution:
* The probability of a photon being emitted at a specific energy level follows the Boltzmann distribution.
* This distribution states that the probability of a photon being emitted at higher energy levels decreases exponentially with increasing energy.
* As wavelength increases, the energy of photons decreases, leading to a higher probability of photons being emitted at lower energy levels.
In summary, the decline of the Planck curve after reaching its peak wavelength is due to the combination of Wien's Displacement Law, energy distribution among photons, quantum mechanical principles, and the Boltzmann distribution. These factors all contribute to a decrease in the spectral radiance at longer wavelengths.
