What formula is used to calculate the energy of a photon?

The formula used to calculate the energy of a photon is E = (hc/λ), where "E" represents the energy, "h" is Planck's constant, "c" is the speed of light in a vacuum, and "λ" (lambda) is the wavelength of the photon. This equation illustrates the relationship between the energy of a photon and its wavelength, demonstrating that shorter wavelengths correspond to higher energy photons, while longer wavelengths correspond to lower energy.

In the context of this formula, Planck's constant links the energy frequency of electromagnetic radiation to its wavelength, which is crucial in understanding phenomena such as the photoelectric effect and the quantized nature of light. The speed of light, a constant, establishes how electromagnetic waves propagate through space.

Other choices represent different physical relationships: the first expression relates to mass-energy equivalence, the third relates power and time, while the last one deals with work done by a force over a distance. However, none of these pertain specifically to the energy of a photon as effectively as the selected formula.