Question solving bmat 2018 Q 27

Practice Question Solving
1

The radioactive isotope carbon-14 is found in living material in small quantities. There are approximately 1000 carbon-14 atoms for every 1015 carbon-12 atoms. Whilst the material is still living this ratio remains constant, because even though the carbon-14 is decaying, it is being constantly replenished. When the material dies the carbon-14 decays and is not replaced. The half-life of carbon-14 is about 6000 years. In a bone the ratio of carbon-14 to carbon-12 atoms is found to be 100:1015.

What is the closest estimate of the age of the bone?

2

hi

ratio ¹⁴C : ¹²C is 1000 : 10¹⁵
in 6000 years half of the original sample of ¹⁴C will have decayed

initial = 1000 ¹⁴C
after 6000 years = 500 ¹⁴C left
after 12000 years = 250 left
after 18000 years = 125 left

since we are told that there is only 100 ¹⁴C left, then a little more than 18000 years have past. The best estimate of the age of the bone is 20000 years

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3

is this in the IMAT 2024 syllabus?

4

Nope it is not included.