Question

The following graph shows the rates of decay for four parent isotopes. Based on the graph, which parent isotope most likely has a half-life of 13 billion years?

A

B

C

D

Answer 1

Just look at the graph, and find a curve that has fallen to
half of its original value 95 = 47.5 in 13 B years.

Do I really hafta tell you which one it is ?

















It's curve ' C ' .

Answer 2

A or B (mostly A)

Step-by-step explanation:

After 14 billion years, approximately 85% of the original parent isotope will still exist, compared to roughly 45% of parent isotope C, 12.5% of parent isotope B, and nearly none of the parent isotope A!

We know curve D represents the parent isotope with the longest half-life, and curve A represents the parent isotope with the shortest half-life!

We also know it cannot be D or C. So we are stuck with curves B and A! However, since parent isotope B has 12.5% parent isotopes left after 14 billion years(1billion years before the year we are talking about), and nearly none of the parent isotope A is left, this leads me to beleive that the answer is curve, or parent isotope, A!

I am sorry if i am wrong though.

Have a marvelous day!