Radiation pressure
Radiation pressure refers to the pressure applied to the surface of an object exposed to electromagnetic waves. If an electromagnetic wave is absorbed into an object, the radiation pressure becomes the density of the radiation energy flux divided by the speed of light. If electromagnetic waves are totally reflected, the radiation pressure is doubled when absorbed. For example, the flux density of the sun's radiant energy on the Earth's surface is 1,370 W / m2, and the radiation pressure available here is 4.6 μPa. In acoustics, radiation pressure is the pressure acting in one direction when a sound wave passes through the interface between two media. It is used for acoustic radiative impulse imaging.