What does a photon energy of a joule equal?

When dealing with "particles" such as photons or electrons, a commonly used unit of energy is the electron-volt (eV) rather than the joule (J). An electron volt is the energy required to raise an electron through 1 volt, thus a photon with an energy of 1 eV = 1.602 × 10-19 J. read more

A photon with a wavelength equal to the Planck length would have an energy of about 7.671 × 10 28 eV or 1.229 × 10 10 joules (12.29 gigajoules). This is roughly the amount of energy produced by the world's most powerful coal-fired power station, the Taichung Power Plant, during a period of 2.25 seconds. read more