<P> An FM radio station transmitting at 100 MHz emits photons with an energy of about 4.1357 × 10 eV . This minuscule amount of energy is approximately 8 × 10 times the electron's mass (via mass - energy equivalence). </P> <P> The highest energy gamma rays detected to date, very - high - energy gamma rays, have photon energies of 100 GeV to 100 TeV (10 to 10 electronvolts) or 0.016 microjoules to 0.016 millijoules . This corresponds to frequencies of 2.42 × 10 to 2.42 × 10 Hz . </P> <P> A photon with a wavelength equal to the Planck length would have an energy of about 7.671 × 10 eV or 1.229 × 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 . </P> <P> During photosynthesis, specific chlorophyll molecules absorb red - light photons at a wavelength of 700 nm in the photosystem I, corresponding to an energy of each photon of ≈ 2 eV ≈ 3 x 10 J ≈ 75 k T, where k T denotes the thermal energy . A minimum of 48 photons is needed for the synthesis of a single glucose molecule from CO and water (chemical potential difference 5 x 10 J) with a maximal energy conversion efficiency of 35% . </P>

The energy of a photon of wavelength gamma is