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WorksheetsAbsolute Age
Total questions: 23
Worksheet time: 12mins
Which is an example of absolute age?
"This trilobite is older than that dinosaur."
"That stromatolite is the absolute oldest fossil I've ever seen."
"Velociraptors lived 71-75 million years ago."
"The oldest sedimentary layer is on the bottom."
The half-life of a radioactive substance depends on the
pressure acting on the material.
amount of the material.
temperature of the material.
composition of the material.
A whale bone that originally contained 200 grams of radioactive carbon-14 now contains 25 grams of carbon-14. How many half-lives have passed since this whale was alive?
1
2
3
4
If carbon-14 is heated, the length of its half-life period would
increase
decrease
remain the same
Carbon-14 can only be used to determine the age of
recently living things (thousands of years old).
recent rocks (thousands of years old).
very old fossils (millions of years old).
very old rocks (millions of years old).
Figure A and B represent the same radioactive substance. Compared to the half-life of the material in figure A, the half-life of the material in each small cube in figure B is
1/8 as long
8 times longer
1/64 as long
the same
How much of the Earth's original U-238 still exists today?
100%
75%
50%
25%
What is the approximate age of an igneous rock that contains only one-fourth of its original potassium-40 content due to radioactive decay?
1.3 x 109 years
3.9 x 109 years
2.6 x 109 years
5.2 x 109 years
Compared to the length of time for the first half-life of a sample of a radioactive isotope, the length of time for the second half-life is
less
greater
the same
What happens to a carbon-14 atom that has gone through radioactive decay?
It disappears.
It turns into nitrogen-14
It becomes soil.
It flips over so the radioactive side is face-down.
This diagram represents a sample of 87Rb. Which diagram represents the correct proportion of 87Rb to its decay product, 87Sr, after two half-lives?
Which radioactive substance would probably be used in dating the recent remains of a plant found in sedimentary deposits?
carbon-14
rubidium-87
potassium-40
uranium-238
This graph shows the relationship between mass and time for a radioactive element during radioactive decay. What is the half-life of the element?
50 billion years
60 billion years
350 billion years
100 billion years
Why is radioactive decay useful for determining absolute age?
Radioactive substances decay at a predictable rate.
All Earth materials contain the same radioactive substances.
The mass of radioactive isotopes in a material is equal to the age of the material.
The half-life of a radioactive substance decreases by half after a certain amount of time.
What is the half-life of Rubidium-87
49 billion years
4.9 billion years
490 billion years
490 million years
What is the half-life of Potassium-40?
1.3 billion years
13 billion years
130 million years
13 million years
What is the disintegration product of Rubidium-87?
87Sr
14N
86Rb
87Pb
How old is a rock that contains 6.25% of its original Potassium-40?
6.5 x109 years
2.6 x109 years
3.9 x109 years
5.2 x109 years
What fraction of U-238 remains in a rock that is 18 billion years old?
1/8
1/16
1/32
1/64
Which isotope was used to determine that the age of a fossil is 30,000 years old?
Uranium-238
Potassium-40
Rubidium-87
Carbon-14
How old is the Earth and the rest of the solar system?
10 billion years
4.6 billion years
65 million years
All solar system objects have very different ages
What can be used for information about Earth's composition and formation?
Meteorites
Fossils
Mars's atmosphere
Solar activity
What do craters tell us about the Moon's history?
The frequency of meteorite impacts.
The number of volcanoes that existed.
The changing composition of the Moon's atmosphere.
The evolution of life on the Moon.
