1. The problem statement, all variables and given/known data If X radiation ionizes 26.2 X 1012 atoms per cemtimeter cubed, what is the ionizing intensity of the radiation measured in roentgens ? 2. Relevant equations 3. The attempt at a solution Help, I have never seen atoms per centimeter cubed before, I know that 1 roentgens is 93.3e-3 J/g, but I don't know how to get atoms per centimeter cubed to that?