The radioactive nuclide ²³⁵U decays with a t _1\2of 703.8 million years. Calculations reveal that there were 10.53 × 10 ²³atoms of ²³⁵U present in an initial sample. If modern spectroscopy shows that 3.25 × 10 ²¹atoms of ²³⁵U now exist in the sample, how long ago did the decay begin?

Question

Quizplus · Accepted Answer

The number of atoms remaining after time t is given by:N(t) = N(0) * (1/2)^(t/t1/2)where N(0) is the initial number of atoms, t1/2 is the half-life, and t is the time elapsed.We can use this equation to solve for t:t = t1/2 * log2(N(0)/N(t))Plugging in the given values, we get:t = 703.8 million years * log2(10.53 × 10^23 / 3.25 × 10^21)t = 5.9 × 10^9 years

The Radioactive Nuclide 235 U Decays with a T

The Radioactive Nuclide ²³⁵U Decays with a T