2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/92649It is shown that the concept of elementary resonator in the theory of thermal radiation implies the indivisible connection between particles (photons) and electromagnetic waves. This wave-particle duality covers both the Wien and Rayleigh-Jeans regions of spectrum.3 pages, submitted to Albert Einstein Century International ConferenceQuantum Physicstext