The plutonium isotope 239Pu has a half-life of 24,000 years, and decays by the emission of a 5.2 MeV alpha particle with an RBE of 10. The alpha particles are low enough energy that they don't penetrate the skin, so plutonium is not dangerous if handled. However, if a fire disperses plutonium as soot particles, they are very dangerous if inhaled. Suppose a soot particle with 2.5 × 1010 239Pu atoms was inhaled. A. (3 pts.) What is the activity of this particle? B. (5 pts.) If the person lived for 20 years after inhaling the soot particle, how much energy was deposited in the lungs? (The half-life is so long that we can assume the activity over this short time period is essentially constant.) Since the range of alpha particles in tissue is very small, the energy is absorbed in a very tiny sphere of tissue with mass 65 ng. C. (3 pts.) What is the radiation dose equivalent over this 20-year period, in Sv? D. (4 pts.) The lethal dose is about 20 Sv. How long would this person actually live if they inhaled this single soot particle?