What are the physics behind radiation pressure?
Well, basically, it depends on whether or not the radiation is absorbed or reflected. So in the diagram above, you see photons that are hitting the block. In the case of reflection, you exert more downwards pressure on the block than in the case of absorption (although in absorption, you’ll still exert downwards pressure on the block). The pressure does not depend on the mass of the radiation – radiation has no mass. Anyways, “Light pressure is equal to the power of the light beam divided by c, the speed of light.” The power of the light beam does depend on the energy of that light beam, so wavelengths of higher frequency do exert more power (and in turn, pressure) per photon. Pressure = Force / Area. As for how the pressure is “stored” in the substance, I think it comes through the conservation of momentum. Light has momentum (it can carry momentum even though it can’t carry mass) [1]. And after the interaction, some of the light changes direction (it goes upwards). So in order for co
