The energy is given by some integer, n , multiplied by Planck's constant, h , and the frequency, f , of the radiation. However, he insisted this was not the way nature actually behaved, merely a model. Indeed, some years later when Einstein used this principle to explain the photoelectric effect, Planck questioned the veracity of the argument. Eventually, as did the whole of the scientific community, he came around and realized the implications. In particular, he had stumbled into the thorny briar of wave-particle duality .
Light seems to propagate like a wave and exchange energy like a particle.
The complacent arrogance of classical physics had eroded. In its place came prolific and enthusiastic scientific inquiry. One such neophyte was a french prince and graduate student in physics, Louis-Victor DeBroglie. Suppose the concept of the light quanta of Planck and Einstein is broadened. DeBroglie's answer was that, indeed, wave-particle duality is not limited to just light.