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

Enter a value for all fields

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

**INSTRUCTIONS**: Choose units and enter the following:

- (
**E**) This is the energy of the photon

**Wavelength of Photon (λ):** The calculator returns the wavelength in meters. However, this can be automatically converted to compatible units via the pull-down menu.

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

where:

- λ= wavelength of the photon
- E = energy of the photon
- h = Planck's constant
- c = speed of light ( 2.998 × 10
^{8}m/s)

The **Astronomy Calculator Suite** includes functions that are useful for studying astronomy and include the following:

- Kepler's 3
^{rd}Law formula T² = (4π • R³)/(G • M) - Small Angle Formula
*Small Angle Formula**α = S / D* - Flux and Magnitude formulas
- Telescope formulas
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**Mass from Luminosity****Mass from Acceleration and Radius****Mass from Speed and Separation****Mass of extra-solar planet from mass of star, radius of star orbit and radius of exoplanet orbit****Mass of extra-solar planet from mass and velocity of star and velocity of planet****Black Hole Mass Calculator****Black Hole Event Horizon Calculator**

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