6. Use the following equations to 238U to 26Pb c calculate the ratio of parent-t
ID: 121650 • Letter: 6
Question
6. Use the following equations to 238U to 26Pb c calculate the ratio of parent-to-daughter isotopes after 2 billion years for the parent-daughter isotope system AUR RES (2 credits) 2t_1 0.697 t1/2 where ND is the numbers of daughter isotopes produced by radioactive decay, Np is the number of parent isotopes remaining, is the decay constant for the parent-daughter isotope system and t1/2 is the half-life for the parent-daughter isotope system. You should use the half-life which is given in chapter 12 of Earth: Portrait of a Planet by S. Marshak Highlight and replace the question mark (2) with your answer. Round off your answer to 2 decimal places. Parent-to-daughter ratio 1 to?Explanation / Answer
The method relies on two separate decay chains, the uranium series from 238U to 206Pb, with a half-life of 4.47 billion years and the actinium series from 235U to 207Pb, with a half-life of 710 million years.
238U to 206Pb half-life is 4.47 billion years
It means after 4.47 billion years parent and daughter both have 50% elements.
So, after 2 years the parent elements has 75% atoms and daughter elements has 25% atoms.
Therefore, the ratio of parent : daughter elements is 25:75 = 1:3
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.