At a particular position, the flux density of particles is 2X10^12 cm^-2s^-1. (a) If the particles are photons, what is the density of photons at

At a particular position, the flux density of particles is 2X10^12 cm^-2s^-1. (a) If the particles are photons, what is the density of photons at that position? (b) If the particles are thermal neutrons (2200 m/s), what is the density of neutrons?