The half-life of carbon-14 is 5730 years. What percentage of carbon-14 remains in a sample after 7 half lives?

1 Answer
Bio
Dec 26, 2015

(frac{1}{2})^7 = 1/128 ~~ 0.781%

Explanation:

After 1 half-life, 1/2 of the C-14 would remain.

After 2 half-life, 1/2 of the 1/2 of the C-14 = 1/4 of the C-14 would remain.

After 3 half-life, 1/2 of the 1/4 of the C-14 = 1/8 of the C-14 would remain.

...

After n half-lives, frac{1}{2^n} of the C-14 would remain.

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