Science 10: Half Life 7.2 pg. 306

pg 306 questions 1-4

What is the length of one half-life of Carbon-14?

5730 years

How many half-lives have passed when there is ¼ of the original amount of carbon-14?

Two half-lives have passed, as each half-life reduces the amount by half, resulting in one quarter of the original amount.

Estimate the percentage of carbon-14 after

A) 5000 years

55%

B) 10,000 years

30%

C) 20, 000 years

~8%

Estimate the time elapsed when the amount of carbon-14 remaining is:

a) 70%

a) ~3000 years

b) 40%

~7500 years

c) 5%

~23,000