Q.Explain the spectral distribution of blackbody radiation.

[!TLDR] At a given T, blackbody radiant power is spread unevenly across wavelengths, peaking at a T-dependent λmax that shifts shorter and taller as T rises. [!ANSWER] At any fixed temperature, the radiant power of a blackbody is unevenly spread across wavelength, forming a singl …

The spectral distribution of blackbody radiation describes how the radiant power emitted by a blackbody, per unit area, per unit wavelength interval, varies as a function of wavelength at a fixed temperature. Lummer and Pringsheim measured this experimentally using a cavity radiator held at several different temperatures, plotting radiant power against wavelength for each. The resulting curves share several key features: (1) at any given temperature, the energy is NOT distributed uniformly across wavelength; (2) the radiant power rises from near zero at short wavelength, reaches a single maximum at a wavelength λmax characteristic of that temperature, then falls back toward zero at long wavelength (λmax is not the longest wavelength emitted -- emission continues, just weaker, well past it); (3) the total area under the curve equals the total energy radiated per unit time per unit area, across all wavelengths -- which is exactly what the Stefan-Boltzmann law (R = σT^4) quantifies; (4) as temperature increases, the peak shifts toward SHORTER wavelengths (λmax decreases), exactly as described by Wien's displacement law; (5) at higher temperatures, the total area under the curve (hence total radiated power) also increases; and (6) at room temperature (around 300 K), the peak lies in the infrared, around 5x10^-5 m, so a room-temperature object emits negligible visible ligh …

Describe the shape of the experimental curves (single peak, area = total energy, peak shift with temperature) and the historical background …

Describing only ONE feature of the curves (e.g. just the peak shift) without mentioning that the curve's area (total power) also grows with temperature, or omitting …