physics

posted by .

The half life of a radioactive sample is 6.93 days.after how many days will only one -tenth of the sample be left behind?

  • physics -

    .1=e^-.693t/6.93
    .1=e^-.1
    ln.1=.1t
    t=-10ln(.1)

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. calc

    The half-life of polonium is 139 days, but your sample will not be useful to you after 95 % of the radioactive nuclei present on the day the sample arrives has disintegrated. For about how many days after the sample arrives will you …
  2. physics-Radioactivity

    1) The number of radioactive nuclei in a particular sample decreases over a period of 15 days to one-seventeenth the original number. What is the half-life (in days) of these nuclei?
  3. Physics 30

    The activity of a sample of a radioactive isotope is 1800Bq. If this isotope has a half-life of 16 days, what is the activity after 16 days?
  4. chemistry

    The half-life for the radioactive decay of calcium-47 is 4.5 days.If a sample has an activity of 4.00uCi after 13.5 days, what was the initial activity of the sample?
  5. math

    You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. You purify a sample of 2 grams. One of your colleagues steals half of it, and eight days later you find …
  6. Physical Science- Help Please!

    Suppose that you are given a 100 gram sample of a radioactive substance with a half-life of 32 days. How many grams will be left after 192 days?
  7. Chemistry

    A radioactive element has a half-life of 6.41 days. What percent of the original sample will be left after 15.0 days?
  8. Pre-Calc

    A radioactive isotope has a half life of 8.1 days. If the sample starts with 25 grams, how much will there be after 90 days?
  9. Algebra 2

    A particular radioactive element has a half life of 10.0 days. How much is left after 30.0 days if the sample started with 345g?
  10. Chemistry

    A particular radioactive element has a half life of 10.0 days. How much is left after 30.0 days if the sample started with 345g?

More Similar Questions