11 of 2011 of 20 Items

Question

13:03

Skip to resources
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.
Skip to navigation

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.