The Planck constant is the quantum of electromagnetic action that relates a photon’s energy to its frequency. The Planck constant multiplied by a photon’s frequency is equal to a photon’s energy. It’s important and lots of people don’t understand what a photon is but they know what light frequency is. This is what is being applied outside here by the serious engineering companies , which physic concept have you applied as an individual either knowingly or unknowingly ?