A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

Radium decreases at the rate of 0.0428 percent per year. a. What is its half-life? (A half-life of a radioactive substance is defined to be the time needed for half of the material to dissipate. b. Write a recurrence relation to describe the decay of radium, where rn is the amount of radium remaining after n years. c. Suppose that one started out with 2 grams of radium. Find a solution for the discrete dynamical system illustrating this process and give the value for r(100), the amount remaining after 100 years.

  • This Question is Closed
  1. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    set \[e^{-0.0428t}=\frac{1}{2}\] solve for t

  2. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    how to solve? X2 +7x + 12 = 0

  3. mathmagician
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Suppose, that at the beginning there are 1000g of radium. After a year there will be 999.572 g. And you want to know, when there will be 500 g of radium. So, use formula\[N _{0}=Ne ^{kt}\]. So, you get \[1000=999.572e ^{k*1}\]. \[k=\ln 0.999572=-0.000428\]. Now, when you know k, you can calculate lifetime:\[0.5=e ^{-0.000428*t}\], \[\ln(0.5)=-0.000428t\] And lifetime is 1619.5 years.

  4. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.