What does “E” represent in the energy equation E = h * frequency?

In the energy equation E = h * frequency, "E" represents the total energy of a photon or electromagnetic wave. This relationship is derived from quantum mechanics, where "h" is Planck's constant, and "frequency" refers to the frequency of the electromagnetic radiation.

The equation shows that the energy of a photon is directly proportional to its frequency, meaning that higher frequency waves (like gamma rays) have more energy than lower frequency waves (like radio waves). This principle is essential in understanding light-matter interactions and forms the basis for technologies such as lasers and semiconductors. Thus, "E" is indicative of the total energy carried by the photon, making it a crucial concept in both chemistry and physics.