Formula: Photon Momentum Wavelength
$$p ~=~ \frac{h}{\class{violet}{\lambda}}$$
$$p ~=~ \frac{h}{\class{violet}{\lambda}}$$
$$\class{violet}{\lambda} ~=~ \frac{h}{p}$$
Momentum
$$ \boldsymbol{p} $$ Unit $$ \frac{\mathrm{kg} \, \mathrm{m}}{\mathrm{s}} $$
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
$$ \lambda $$ Unit $$ \mathrm{m} $$
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
$$ h $$ Unit $$ \mathrm{Js} = \frac{ \mathrm{kg} \, \mathrm{m}^2 }{ \mathrm{s} } $$
Planck's constant is a physical constant (of quantum mechanics) and has the value: \( h ~=~ 6.626 \cdot 10^{-34} \, \mathrm{Js} \).