SOLUTION: Radioactive Decay. Strontium-90 has a half-life of 28 years. How long will it take for 40 grams of this to decay to 5 grams? Apply the formula N= N0e^rt, where N is the number of g

Algebra.Com
Question 1126133: Radioactive Decay. Strontium-90 has a half-life of 28 years. How long will it take for 40 grams of this to decay to 5 grams? Apply the formula N= N0e^rt, where N is the number of grams.

Round your answer to the nearest year.
Found 4 solutions by solver91311, ikleyn, josgarithmetic, Alan3354:
Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!


Physics problem. What is r for a half-life of 28 years? Once you know that, plug in your numbers and solve for .


John

My calculator said it, I believe it, that settles it
Answer by ikleyn(52818)   (Show Source): You can put this solution on YOUR website!
.
The ratio  of 5 grams to 40 grams is   = , which is  (fortunately !) exactly  .


It means that 40 grams will decay to 5 grams in the time which is exactly thrice the half-period, or exactly in 3*28 = 84 years.

Solved.

----------------

The instruction placed at the end of your post is VERY BAD advise on how to solve the given problem.

The much simpler way is that I showed in my post.


Answer by josgarithmetic(39621)   (Show Source): You can put this solution on YOUR website!
Half-life of 28 years given







Your already know that for this, t=28.



You should be able to use this for answering the question and using the equation in your given instructions.
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Radioactive Decay. Strontium-90 has a half-life of 28 years. How long will it take for 40 grams of this to decay to 5 grams? Apply the formula N= N0e^rt, where N is the number of grams.
------------
Years    Remaining
 0         40
 1         20
 2         10
 3          5

RELATED QUESTIONS

strontium-89 has a half-life of 50.6 days. How long will it take for 20 grams of... (answered by ankor@dixie-net.com)
strontium-90 is a waste product from nuclear fission reactors. It's half-life is 28 years (answered by jsmallt9)
CAN SOMEONE HELP WITH THIS WORD PROBLEM? Strontium-90 is a waste product from nuclear... (answered by scott8148)
Strontium-90 has a half-life of 29 years. How long will it take for an initial sample of... (answered by ewatrrr)
The half-life of strontium-90 is 28 years. How long will it take a 44 mg sample to decay... (answered by Fombitz)
The half-life of strontium-90 is 28 years. How long will it take a 72 mg sample to decay... (answered by richard1234)
uranium-235 is used as fuel for some nuclear reactors. it has a half life of 710 million... (answered by ankor@dixie-net.com)
Strontium 90 is a radioactive material that decays according to the function... (answered by Boreal)
8. Radioactive materials like uranium follow the law of uninhibited decay, which is an... (answered by josgarithmetic)