Solution to task 572 from Chertov´s for extramural stud

Solution to task 572 from Chertov´s for extramural stud

572. The pressure p of light with a wavelength of λ = 40 nm, incident normally on a black surface, is 2 nPa. Determine the number N of photons incident during t = 10 s on the area S = 1 mm2 of this surface.