`E = \frac{h c}{\lambda}`

Enter a value for all fields

The Photon Energy from Wavelength calculator compute the energy of a photon based on Planck's constant (h), the speed of light (c) and the wavelength of the photon ( λ).

INSTRUCTIONS: Choose units and enter the following:

• ( λ) This is the wavelength of the photon

Energy of Photon (E): The calculator returns the energy in Joules.  However, this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The energy of a photon depends only on its wavelength.  The formula for the energy of a photon is:

          E= h•c / λ

where:

• E = energy of the photon
• h = Planck's constant 
• c = speed of light ( 2.998 × 10⁸ m/s)
• λ= wavelength of the light

Note the following relations are also true:

`f = c/λ`

`f = E/h`

`E = (h⋅c) /λ` 

`λ = (h⋅c)/E`

`E = h * f`

where:

• E = energy of light
• f = frequency
• h = Planck's Constant
• c = Speed of Light in a vacuum 

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• Kepler's 3^rd Law formula T² = (4π • R³)/(G • M)
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