(a) You direct a 13.5 mW laser beam toward a surface at normal incidence. The surface is made of a material that completely absorbs the radiation. What is the radiation pressure on the surface if the cross section of the beam has a diameter of 2.85 mm when it arrives at the surface?
(b) You now direct the same laser beam, with the same power and beam cross section, at normal incidence on a mirror where 100% of the beam is reflected from the surface. What is the total pressure on it due to the incident and reflected energies?