# Formula Photon Momentum    Wavelength

## Momentum

Unit
Momentum of a photon (light particle). The smaller the wavelength, the larger the momentum. Ultraviolet photons thus have a larger momentum than photons from the visible wavelength range.

This momentum can be transferred to atoms, for example, to slow them down or decelerate them.

## Wavelength

Unit
Wavelength of light. This is the distance between two wave crests / troughs of a monochromatic light source. So it tells within which distance $$\lambda$$ exactly one periodic oscillation of the light wave was completed.

## Planck's Constant

Unit
Planck's constant is a physical constant (of quantum mechanics) and has the value: $$h ~=~ 6.626 \cdot 10^{-34} \, \mathrm{Js}$$.