The following questions are designed to give you practice using a logarithmic scale on a graph and to learn more about radioactive decay. These questions are based on figments of the imagination of a certified Dr. Egghead assistant. In order to answer the questions you will need to refer to both a graph on the decay of Plutonium-238, and a table on the radiological properties of plutonium. (See below.)
First step: You'll need a worksheet that graphs the decay of Plutonium-238. We suggest printing out this page so you can use it to answer the questions below.
Next step: To answer some of the questions below, you will need to refer to the table of the radiological properties of plutonium. You can print this out or not, as your heart desires.
OK! You're ready to begin. As with other on-line worksheets, we recommend you print this page out to make it easier to work with. Have fun!
1. What are the units used on the y-axis of this graph?
2. What is 10,000 in scientific notation? What is it in E notation?
3. What is the mass, in kilograms, of 10,000 curies of Pu-238 (Hint: What is the specific activity of Pu-238)?
4. After one half-life, how many curies of the original Pu-238 remain?
5. How many years, or half-lives, must elapse for the original radioactivity of the Pu-238 to decay to 2,500 curies?
6. Using the graph please answer the following question. After 72 years about how many curies of the original plutonium-238 are left?
A real stumper!!!!
7. When does the mass of the original Pu-238 equal about 9 grams?
Institute for Energy and
Environmental Research
Comments to Outreach Coordinator, Pat Ortmeyer: ieer@ieer.org
Takoma Park, Maryland, USA
Last Updated April 17, 1996