What is the energy of a photon given by?

The energy of a photon is accurately described by the relationship (E = hf). In this equation, (E) represents the energy of the photon, (h) is Planck's constant, and (f) is the frequency of the electromagnetic wave. This relationship shows that the energy of a photon is directly proportional to its frequency, meaning that higher frequency photons (such as gamma rays) carry more energy than lower frequency ones (such as radio waves).

This concept comes from quantum mechanics, where photons are considered quantized packets of electromagnetic radiation. Planck’s constant is a fundamental constant that bridges the gap between the macroscopic and quantum worlds, highlighting how energy, frequency, and physical constants interact.

The other options describe different physical concepts. For instance, (E = mc²) is the famous equation from Einstein's theory of relativity, relating mass and energy, but it does not apply specifically to photons. (E = ½ mv²) is the kinetic energy formula for classical mechanics and is not suitable for describing photon energy. Lastly, (E = qV) relates the energy gained by a charge (q) in an electric field (V), which again is not relevant to the