Photon Energy-Frequency Calculator Formula

Understand the math behind the photon energy-frequency calculator. Each variable explained with a worked example.

Use the Photon Energy-Frequency Calculator

Formulas Used

Energy

energy_j = 6.626e-34 * frequency

Energy (eV)

energy_ev = 6.626e-34 * frequency / 1.602e-19

Wavelength

wavelength = 2.998e8 / frequency

Variables

VariableDescriptionDefault
frequencyFrequency(Hz)500000000000000

How It Works

Photon Energy from Frequency

A photon's energy is directly proportional to its frequency.

Formula

E = h f

  • *h* = 6.626 x 10^-34 J s (Planck constant)
  • *f* = frequency in Hz

    • The wavelength is lambda = c / f. Higher frequency (shorter wavelength) means higher energy.

    Worked Example

    Green light at 500 THz (5e14 Hz).

    frequency = 500000000000000
    1. 01E = h f
    2. 02E = 6.626e-34 * 5e14
    3. 03E = 3.313e-19 J
    4. 04E = 3.313e-19 / 1.602e-19 = 2.069 eV
    5. 05lambda = 3e8 / 5e14 = 6e-7 m = 600 nm

    Frequently Asked Questions

    What is the energy of a visible light photon?

    Visible light spans about 1.65 eV (red, 750 nm) to 3.1 eV (violet, 400 nm).

    How does photon energy relate to temperature?

    The peak frequency of thermal radiation is proportional to temperature (Wien law). At room temperature, thermal photons are in the infrared.

    Can a photon have any energy?

    In principle yes, from radio waves (tiny energy) to gamma rays (MeV or more). The energy is quantised for a given frequency but the frequency itself is continuous.

    Ready to run the numbers?

    Open Photon Energy-Frequency Calculator