Watercolor portrait of Max Planck (1858-1947). Planck was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918. Planck deduced the relationship between the energy and frequency of radiation, E=hv, where h is a universal constant, now called Planck’s constant. Planck published this derivation in a 1900 paper, which was based on the revolutionary idea that the energy emitted by a resonator could only take on discrete values.