Final answer:
Planck's constant is the physical constant that relates energy to the frequency of light, denoted by h in the equation E = hf, and it's named after the German physicist Max Planck.
Step-by-step explanation:
The physical constant relating the energy and frequency of light is named after Max Planck. The famous equation E = hf, where E represents the energy of a photon, f is the frequency of the light, and h is Planck's constant. Planck's constant is a fundamental constant in physics, deeply intertwined with the quantum theory developed by Planck, and it has a value of approximately 6.626 × 10-34 joule-seconds (J·s). This constant illustrates that higher-energy photons have a higher frequency (and thus a shorter wavelength), while lower-energy photons have a lower frequency.