half life math
2014-03-10 12:41 am
if a radioactive substance has a half life of 10 days, in how many days will 1/8 of the initial amount be present?
回答 (2)
2014-03-10 12:48 am
✔ 最佳答案
After 10 days, (1/2) leftAfter 20 days, (1/2)(1/2) = (1/4) left
After 30 days, (1/2)(1/2)(1/2) = (1/8) left
2014-03-09 16:50:39 補充：
OR (1/2)^(days/10)
(1/8) = (1/2)^3
3 = (days/10)
days = 3X10 = 30
2014-03-10 1:11 am
Thank you very much Mr. Kwok,
You help me a lot and you make everything clear :)
then I use the exponential decay function.
0.5V=Ve^(-10k)
k=0.069314718
then
(1/8)V=Ve^(-kt)
t=30.00000002
Time=30 days(corr to integer)
2014-03-09 17:11:58 補充：
your way is much faster and straightforward of course!!
You help me a lot and you make everything clear :)
then I use the exponential decay function.
0.5V=Ve^(-10k)
k=0.069314718
then
(1/8)V=Ve^(-kt)
t=30.00000002
Time=30 days(corr to integer)
2014-03-09 17:11:58 補充：
your way is much faster and straightforward of course!!
收錄日期: 2021-04-27 20:35:13
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20140309000051KK00108