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4.3 Exponential Decay

4.3 Exponential Decay
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  • Math Help

    Here are some additional algebraic steps for finding the exponential decay rate in Example 6.

    So, r = 0.25. Note that in the context of the problem in Example 6, r = 0.25 corresponds to an exponential decay rate of 25% every 10,000 years.

    Download the spreadsheet to access the data used in Example 6.

  • Consumer Suggestion

    Radiation has existed in rocks, soil, water, and plants since the Earth's formation. The use of these radioactive materials has been used in medicine, power generation, and consumer products.

    Nuclear medicine uses radioactive substances to image the body and treat disease. For more information on how nuclear medicine works, visit Discovery Health.

  • Checkpoint Solution

    It took the plutonium 80,000 years to decay to one tenth its original size (from 10 grams to 1 gram).

    Because it is decaying at a constant exponential rate, it will take 80,000 more years to decay to one tenth its size again (from 1 gram to one tenth gram).

    You can check this result using the formula for exponential decay

    or by downloading the spreadsheet.

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    system user
    Guest   6 years ago |
    There are dozens of nuclear waste sites in the United States. Here is a map from Wikipedia.

    en.wikipedia.org/wiki/File:Nuclear_waste_locations_USA.jpg
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