Photon Momentum Formula

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


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.


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


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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