[填空题]
A cancer patient is un(f dahto l -i4:xpzpm/ge.,ww5 rq*/ndergoing radiation therapy in whichh;fs, bj.: :bda o8myp protons with an energy of 1.2 MeV are incident on a 0.25-kgpaf :dsj. mb,:8hoby; tumor.
(a) If the patient receives an effective dose of 1.0 rem, what is the absorbed dose?
(b) How many protons are absorbed by the tumor? Assume $QF = 1$. $ \times 10^{10}\ \text{p}$