Imagine you're conducting an experiment to measure the energy of photons emitted from a heated metal surface. In this context, which principle explains why the energy of the emitted photons increases with temperature?

The principle that explains this is Wien’s displacement law, which comes from Planck’s quantum theory of black‑body radiation. It states that the wavelength at which a heated object emits most strongly is inversely proportional to its temperature. Because the photon energy is inversely proportional to wavelength (E = hc/λ), a shorter peak wavelength means higher photon energy. For example, a metal heated from 500 K to 1000 K will shift its peak emission from about 5 µm to 2. 5 µm, doubling the photon energy from roughly 0.