Question

3)How old is a sample that contains 87.5% of the daughter isotope Nitrogen-14? *
1 point
5730 Years
11460 Years
17190 Years
22920 Years
3A) Using the info from question 3, How many half-lives have passed? *
1 point
1
2
3
4
5
3B) Using the info from question 3, What % of Carbon-14 is left? *
1 point
100%
84.1%
70.7%
50%
25%
12.5%
6.25%
4) How much time has elapsed if only ½ of a half-life has expired for Uranium-238? *
1 point
0 Years
1.125 BY
2.25 BY
4.5 BY
9 BY
4A) Using the info from question 4, How many half-lives have elapsed if 31.5 billion years has gone by? *
1 point
1
2
3
4
5
6
7
4B) Using the info from question 4, What % of the daughter isotope would remain after 22.5 billion years? *
1 point
0%
15.9%
29.3%
50%
75%
87.5%
93.8%
96.9%
5) If you started off with 2000 atoms of a radioactive substance and its half-life was 10 years, how many years would it take to get that radioactive substance down to 15.625 atoms? *
1 point
10 Years
20 Years
30 Years
40 Years
50 Years
60 Years
70 Years
5A) Using the info from question 5, How many half-lives have occurred? *
1 point
1
2
3
4
5
6
7

Answer 1

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