Today,uranium contains 0.72% ²³⁵U (half-life = 0.70 billion years)and 99.28% ²³⁸U (half-life = 4.5 billion years).At a time 1.9 billion years ago,what was the fraction of ²³⁵U in uranium?

Question

Quizplus · Accepted Answer

The fraction of ^235U in uranium 1.9 billion years ago can be calculated using the decay formula. Given the half-life of ^235U is 0.70 billion years, we can determine how many half-lives have passed and calculate the initial fraction. The correct calculation shows that the fraction was approximately 3.53%.

Today,uranium Contains 0