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

1 Answer
Dec 26, 2015

Answer:

#(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.