A rock containing 238 92 U and 206 82 Pb was examined to determine its approximate age Analysis showed the ratio of 206 82 Pb atoms to 238 92 U atoms to be 0 115 Assuming that no lead was originally present, that all the 206 82 Pb formed over the years has remained in the rock, and that the number ...

The problem can be solved using the integrated firstorder rate law N In kt No Thus whe ...

A rock containing 238 92 U and 206 82 Pb was examined to determine its approximate age.

Question:

A rock containing ²³⁸₉₂U and ²⁰⁶₈₂Pb was examined to determine its approximate age. Analysis showed the ratio of ²⁰⁶₈₂Pb atoms to ²³⁸₉₂U atoms to be 0.115. Assuming that no lead was originally present, that all the ²⁰⁶₈₂Pb formed over the years has remained in the rock, and that the number of nuclides in the intermediate stages of decay between ²³⁸₉₂U and ²⁰⁶₈₂Pb is negligible, calculate the age of the rock. The half-life of ²³⁸₉₂U is 4.5 × 10⁹ yr.