Radioactive isotopes decay according to a first order process. If N(t) is the number of atoms of a radioactive isotope at time t, then N(t)=N(0)e^(-kt).
A. cu-64 (1/2 = 12.8 hr) is used in brain scans for tumors and in studies of Wilson/s disease, a genertic inability to metabolize copper. how many days are requird before the dose of cu-64 administered to a patient drops to 0.10% of its initial activity? (Cu isnt leaving the body by any process other than its normal radioactive decay.)
B. U-238 decays to Pb-206 with a half life of 4.51*10^9 years, A sample of ocean sediment contains 1.50 mg of U-238 and 0.460 mg of Pb-206. estimate the age of the sediment. (assume that Pb-206 is formed only as a resultant of the decay of U-238; you may also assume that Pb-206 is stable and does not itself decay.)