Go to CCP Homepage Go to Materials Page Go to Precalculus Materials Go to Table of Contents
Go Back One Page Go Forward One Page

Radioactive Wastes

Part 3: Isotope Half-Lives

In this part of the module, we will use other sites on the World Wide Web. Remember that you can return to this page from a remote site by using the BACK button on your browser.

  1. The Environmental Health and Safety office at UC Santa Cruz has a useful online decay calculator for six specific isotopes. Use it to calculate the decay of 500 milliCuries (mCi) of phosphorus-32 from your choice of "reference date" to today. Record the output in your worksheet: current amount, lambda value, and time elapsed.

  2. Calculate the half-life for 32p.

  3. How long does it take for 500 mCi of 32p to decay below 1 microCurie (uCi)? Plot the decay function for 32p over this length of time. How does this decay time compare with the Duke EPD guideline of 10 half-lives?.

  4. Repeat Steps 1-3 for 500 mCi of iodine-125 (125I).

  5. Iodine-131 is not one of the isotopes in the UCSC decay calculator. To find its half-life (and more about it than you ever wanted to know), explore the Table of the Nuclides page at Brookhaven National Lab. Record your findings, and repeat Step 3 for 131I.
Go to CCP Homepage Go to Materials Page Go to Precalculus Materials Go to Table of Contents
Go Back One Page Go Forward One Page

modules at math.duke.edu Copyright CCP and the author(s), 1998-2000