# Earlier in the chapter, we learned that it was possible to calculate the concentration of a…

Earlier in the chapter, we learned that it was possible to

calculate the concentration of a radioactive material N(t) from a simple

equation of the form. N(t) = Noe−λt where No is the current

concentration at time = 0. Part 1: Suppose that we would like to use this

equation to estimate the amount of Uranium-238 that existed on the Earth 4.5

billion years ago—or about the time the Earth was rst formed. If No 238 is the

concentration today, what was the concentration of U-238 on the Earth 4.5

billion years ago? Part 2: Assuming that No 235 is the concentration of U-235

today, what was the concentration of U-235 on the Earth 4.5 billion years

ago? Part 3: Based on the results of parts 1 and 2, what was the average

natural “enrichment” of Uranium-235 in the uranium ore at the time (4.5 billion

years ago)