# Photon Momentum Formula

A photon which is an elementary particle and is massless, it has a linear momentum which is related to its energy and wavelength.

Photon momentum = Plank's constant / photon's wavelength

The equation is:

p = h / λ

Where:

P: photon momentum

h:Plank's constant

λ: photon's wavelength

Photon Momentum Formula Questions:

1) Calculate the momentum of a photon which has a wavelength of 400 nm.

Answer:

We replaced the wavelength and the Plank's constant in the photon momentum equation

p = (6.626 x 10^{-34} J.s) / 400 x 10^{-9} m

p = 1.65 x 10 ^{-27} kg .m / s

2) Calculate the wavelength which has a photon with a momentum of 5.4 x 10 ^{-20} kg .m /s

Answer:

First we cleared the photon's wavelength of the photon momentum equation

λ = h / p

Now we replaced the data

λ = (6.626 x 10^{-34} J.s) / 5.4 x 10^{-20} kg .m / s

λ = 1.22 x 10^{-14} m

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