Question

²³⁸U decays to ²⁰⁰Pb with a half-life of 4.47 x10⁹ y. This happens in a number of steps. Can you justify a single half-life for this chain of processes ? A sample of rock is found to contain 2.00 mg of ²³⁸U and 0.600 mg of ²⁰⁰Pb. Assuming that all the lead has come from uranium, find the life of the rock.

Answer 1

Half life period can be a single for all the process. It is the time taken for 1/2 of the uranium to convert to lead.