Find the energy of one photon E = h f in joules and electronvolts.
| Energy (eV) | – |
| Energy (J) | – |
Use this calculator for a single photon: energy is Planck’s constant times frequency. The same energy is shown in joules and in electronvolts (divide by e).
Visible light around 5×10¹⁴ Hz is a couple of eV. Radio photons are tiny; X-ray photons are thousands of eV. If you know wavelength instead, frequency is wave speed divided by λ (in vacuum, c / λ). This is one photon, not a beam power.
Frequency (Hz): Frequency of the light, in hertz.
Energy (eV): E / e, convenient for atomic scales.
Energy (J): E = h f in joules.
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