Radioactive Decay Questions

1. According to the ESRT, which element is used by scientists for radioactive dating of rocks?

Cobalt-60
Plutonium-244
Potassium-40
Silicon-28

2. Based on the graph, what is the half life of this element?



5000 years
10,000 years
15,000 years
20,000 years

3. According to the ESRT, which radioactive element would be most useful for determining the age of clothing that is thought to have been worn 2000 years ago?

Carbon-14
Potassium-40
Uranium-238
Rubidium-87

4. The decay rates of radioactive substances remain constant when the substances are subjected to different temperature and pressure conditions. The best inference that can be drawn from this statement is that decay rates are

Independent of external factors
Independent of the isotopes composition
affected by the mass of the isotope
Affected by pressure but not by temperature

5. If a sample of a radioactive substance is crushed, the half-life of the substance will

Increase
Decrease
Remain the same

6. Which radioactive substance shown on the graph has the longest half life?



A
B
C
D

7. The table gives information about the radioactive decay of carbon-14. What is the amount of original carbon-14 remaining after 34,200 years?



1/8 g
1/16 g
1/32 g
1/64 g

8. Which radioactive element is represented by the decay curve shown on the graph?



Carbon-14
Potassium-40
Uranium-238
Rubidium-87

9. Isotopes of an element

Have different numbers of protons
Have different numbers of electrons
Have different numbers of neutrons
Are always radioactive

10. A sample of a substance originally contained 8g of carbon 14 and no nitrogen 14. How much nitrogen-14 will the sample contain after 11,400 years?

0 g
2 g
4 g
6 g

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