HW

Half-Life of Radioactive Isotopes

Go to the Wikipedia list of radioactive isotopes by half-life (https://en.wikipedia.org/wiki/List_of_radioactive_isotopes_by_half-life#106_seconds ) and choose a radioactive isotope in the 106 seconds list.

Name of your chosen radioactive isotope:

If the half-life is given in days, calculate its half-life in weeks and years. If it is given in years, calculate its half-life in days and weeks. Write all three below. Round your answers to 4 decimal places.

Half-Life in Days: Half-Life in Weeks: Half-Life in Years:

Moving forward, we will use the half-life in days, so t will be measured in days. Using the formula for exponential decay (A = A0ekt) and the half-life for your radioactive isotope, calculate k. Make sure to get your value of k to 8 decimal places.

k = ______________

Write an equation for your radioactive isotope plugging in k, but no specific value of t (for example, A = A0e

-.00027154t ).

A = _____________

Now, use your equation to find how long it will take for the radioactive isotope to decay to 20% of its original amount. Round your answer to the nearest tenth.

days