Question

11 of 2011 of 20 Items
13:03






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Question
Scientists found a fossilized bone from an organism at an excavation site in North Dakota. When they took the bone back to the lab, they realized that the bone had only 12.5% of the total carbon-14 left. Based on the amount of carbon-14 left in the bone how old is the bone if the half-life of carbon-14 is 5730 years?
Responses
A 5730 years old5730 years old
B 17,190 years old17,190 years old
C 71,625 years old71,625 years old
D Cannot determine answer based on information given.Cannot determine answer based on information given.
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Answer 1

To determine the age of the bone based on the remaining carbon-14, we can use the half-life of carbon-14, which is 5730 years.

1. **Calculate the number of half-lives** that have passed to reduce the carbon-14 to 12.5%.
- 100% to 50% (after 1 half-life)
- 50% to 25% (after 2 half-lives)
- 25% to 12.5% (after 3 half-lives)

Therefore, 12.5% indicates that 3 half-lives have passed.

2. **Calculate the age** of the bone:
\[
\text{Age} = \text{Number of half-lives} \times \text{Half-life of carbon-14}
\]
\[
\text{Age} = 3 \times 5730 \, \text{years} = 17190 \, \text{years}
\]

Thus, the bone is **17,190 years old**.

The correct response is **B: 17,190 years old**.