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WorksheetsRadiometric Dating and Radioactive Decay
Total questions: 18
Worksheet time: 20mins
Name
Class
Date
1.
When an unstable radioactive atom decays, it usually turns into:
a)
a more stable atom
b)
a less stable atom
c)
the exact same atom but with less pure energy
d)
empty space
2.
Radiometric dating is possible because the rates of decay of radioactive isotopes _____.
a)
change over time
b)
change from place to place
c)
are constant
d)
vary widely
3.
The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.
a)
the daughter product
b)
geologic time
c)
the half-life
d)
the half-time
4.
According to the graph, what fraction of the original parent isotope still exists after 3 half lives?
a)
0,5000 g
b)
0,2500 g
c)
0,1250 g
d)
0.0625 g
5.
You find a rock sample with radioactive atoms present. If 12.5% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)
a)
zero
b)
1
c)
2
d)
3
6.
You find a rock sample with radioactive atoms present. If 25% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)
a)
zero
b)
1
c)
2
d)
3
7.
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives?
a)
25 years
b)
200 years
c)
400 years
d)
800 years
8.
Suppose you found a material in which 12.5% of the original radioactive atoms were still present. If the half-life of an atom is 60 years, how old is the material?
a)
30 years old
b)
60 years old
c)
120 years old
d)
180 years old
9.
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been ten half-lives?
a)
10 years
b)
100 years
c)
1000 years
d)
10000 years
10.
Using ESRT (A) [Radioactive Decay Data], what is the half-life in standard notation of carbon-14?
a)
5,700 years
b)
57,000 years
c)
570,000 years
d)
5,700,000 years
11.
Using ESRT (A) [Radioactive Decay Data], what is the half-life in standard notation of Uranium-238?
a)
4,500 years
b)
450,000 years
c)
4,500,000 years
d)
4,500,000,000 years
12.
The table shows the radioactive decay of carbon-14. Part of the table has been left blank.
After 22,800 years, approximately what percentage of the original carbon-14 remains?
After 22,800 years, approximately what percentage of the original carbon-14 remains?
a)
15%
b)
12.5%
c)
6.25%
d)
3.125%
13.
The graph shows the generalized rate of decay of radioactive isotopes over 5 half-lives.
If the original mass of a radioactive isotope was 24 grams, how many grams would remain after 3 half-lives?
If the original mass of a radioactive isotope was 24 grams, how many grams would remain after 3 half-lives?
a)
12
b)
24
c)
3
d)
6
14.
Which radioactive isotope takes the greatest amount of time to undergo radioactive decay?
a)
Carbon-14
b)
Potassium-40
c)
Uranium-238
d)
Rubidium-87
15.
The graph shows the radioactive decay of a 50-gram sample of a radioactive isotope.
According to the graph, what is the half-life of this isotope?
According to the graph, what is the half-life of this isotope?
a)
100 years
b)
150 years
c)
200 years
d)
300 years
16.
Potassium-40 is useful for radioactive dating of Earth's rocks because the half-life of potassium-40
a)
decreased as the amounts of 40Ar and 40Ca in the rock increased
b)
remained constant during the radioactive decay process
c)
increased as pressure from the overlying sedimentary rock increased
d)
was shortened by the high temperature of the magma that formed the rock
17.
The graph shows the decay of a radioactive material over time.
How long does it take for this radioactive material to decay through 2 half-lives?
How long does it take for this radioactive material to decay through 2 half-lives?
a)
1 x 103 years
b)
5 x 103 years
c)
10 x 103 years
d)
40 x 103 years
18.
The characteristic of the radioactive isotope uranium-238 that makes this isotope useful for accurately dating the age of a rock is the isotope’s
a)
organic origin
b)
constant half life
c)
common
occurrence in sediment
occurrence in sediment
d)
resistance to weathering
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