Comprehensive proof of Planck's energy relation for photons is not definitively available in science, similar to the status of Einstein's Special Theory of Relativity, which has not been contradicted by experiments but cannot be considered absolute proof. The scientific community accepts Planck's relation as valid due to its consistent satisfaction of all known tests. Users are encouraged to explore recommended resources for a deeper understanding of photon energy determination. Engaging with these materials can clarify doubts and foster further discussion. Overall, Planck's energy relation remains a foundational concept in physics.