Multiple choice

Carbon-14 (half-life of 5760 years) is used to determine the age of fossils. A sample contains 200 mg of C-14. How long will it take to reduce C-14 in the sample to 25 mg?

  1. 5760 years

  2. 11520 years

  3. 17280 years

  4. 23040 years

  5. 28800 years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For 17280 years, the number of half-life (n) = 3 Cn = (1/2)n= (1/2)3 = 1/8 1/8 of 200 mg = 25 mg So, after 17280 years, the amount of C-14 in the sample will be reduced to 25 mg.

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