1.) A 2.0-kg tumor is being irradiated by a radioactive source. The tumor receives an absorbed dose of 10 Gy in a time of 910 s. Each disintegration of the radioactive source produces a particle that enters the tumor and delivers an energy of 0.39 MeV. What is the activity N/ t (in Bq) of the radioactive source?
2.) A beam of nuclei is used for cancer therapy. Each nucleus has an energy of 108 MeV, and the relative biological effectiveness (RBE) of this type of radiation is 16. The beam is directed onto a 0.230-kg tumor, which receives a biologically equivalent dose of 210 rem. How many nuclei are in the beam?