Question

The half-life of carbon-14 is 5,730 years. How many grams of parent material will remain from a 120-gram sample of carbon-14 after 2 half-lives?

90

60

30

15

Answer 1

after each half life the amount of C-12 decreases by half

after two half-lives the amount of C-12 has decreased by half twice,

Answer 2

Thanks

Answer 3

\[120\times\frac 12\times \frac 12\]

Answer 4

I am looking at the answer as 30

Answer 5

good good

Answer 6

a 120g sample of pure C-14 will be 30g after 11460 years

Answer 7

*i mean C-14 in my first post not C-12.

C-12 is radioactively stable.