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WorksheetsHalf-life practice
Total questions: 10
Worksheet time: 13mins
Name
Class
Date
1.
What is Half-life?
a)
The amount of time it takes for some of the nuclei in a sample of the isotope to decay
b)
The amount of time it takes for half the electrons in a sample of the isotope to decay
c)
The amount of time it takes for half the nuclei in a sample of the isotope to decay
d)
the amount of time it takes to double the nuclei in a sample of the isotope to decay
2.
The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?
a)
100.0g
b)
50.0g
c)
12.5g
d)
8.5g
3.
Pd-100 has a half-life of 3.6 days. If one had 620,310,740 atoms at the start, how many atoms would be present after 21.6 days?
a)
9.7x106 atoms remain
b)
97.0x106 atoms remain
c)
0.97x106 atoms remain
d)
9.7x105 atoms remain
4.
Fermium-253 has a half-life of 0.334 seconds. A radioactive sample is considered to be completely decayed after 10 half-lives. How much time will elapse for this sample to be considered gone?
a)
0.334 seconds
b)
3.34 seconds
c)
1.77 seconds
d)
13.4 seconds
5.
After the third half-life, how much of the sample is left?
a)
1/2
b)
1/3
c)
1/16
d)
1/8
6.
The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.20 days?
a)
312.5%
b)
31.25%
c)
.3125%
d)
3.125%
7.
Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?
a)
0.25g
b)
2.5g
c)
25g
d)
80g
8.
If 10 mg of iodine 131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.
a)
1.25mg
b)
1.25g
c)
10g
d)
10mg
9.
The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g?
a)
3.0g
b)
0.25mg
c)
0.3g
d)
0.25g
10.
If the half-life of uranium-232 is 70 years, how many half-lives will it take for 10 g of it to be reduced to 1.25 g?
a)
1 half-life
b)
2 half-lives
c)
3 half-lives
d)
4 half-lives
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