ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: boysenberry on November 01, 2009, 07:17:59 pm
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The half-life of radioactive elements can be used to determine the age of fossils. Uranium-235 has a half life of approximately 700 million years. If the rock surroudning a fossil was found to have 1/64th of the original amount of uranium-235, then it could be concluded that the age of the fossil is approximately:
A) 700 million years
B) 10 million years
C) 42000 million years
D) 25000 million years
How do you do this question? Do you need a calculator? :-\
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1 half life=1/2 the amount
2 half lives=1/4 the amount
...etcetc
6 half lives=1/64th the amount
6 times 700 million is 42000 million years.
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6 times 700 million is 42000 million years.
i guess that makes sense. :)