strålningsdruck
Strålningsdruck, or radiation pressure, is the pressure exerted by electromagnetic radiation on matter as photons transfer momentum to the surface they strike. Photons carry momentum p = E/c, so absorbing light imparts momentum F/c per unit area equal to the incident energy flux F; if the surface reflects light, the momentum transfer is doubled, giving 2F/c.
For oblique incidence, general expressions depend on the angular distribution of the radiation. For a perfectly
In a cavity or isotropic radiation field, the pressure relates to the energy density u by P
Strålningsdruck has several practical and theoretical roles. It was first measured experimentally by Pyotr Lebedev around
Measuring radiation pressure informs material properties such as reflectivity and absorptivity and remains a fundamental factor