SwedishPersian Posted January 3, 2010 Report Share Posted January 3, 2010 The half life of an unstable element is 12 days. Find the activity of a given sample of this element after 20 days if the initial activity was 3,5 MBq.HELP Reply Link to post Share on other sites More sharing options...
sweetnsimple786 Posted January 6, 2010 Report Share Posted January 6, 2010 To find the amount of something remaining, you use N=No(1/2)t/t1/2It's really similar to the interest formula you'd use in math. A=P(1+rt)nt or something like that...Anyways, use the first formula, but instead of saying N, say A for activity. Final activity = (3.5MBq)(1/2)20/12 = 1.1MBq, if I entered that in my calc correctly. In this case, you just had to know the formula, right? Reply Link to post Share on other sites More sharing options...
AmelieRory Posted January 16, 2010 Report Share Posted January 16, 2010 To find the amount of something remaining, you use N=No(1/2)t/t1/2It's really similar to the interest formula you'd use in math. A=P(1+rt)nt or something like that...Anyways, use the first formula, but instead of saying N, say A for activity. Final activity = (3.5MBq)(1/2)20/12 = 1.1MBq, if I entered that in my calc correctly. In this case, you just had to know the formula, right?Yeah. If this comes up on the exam, just remember to use your data booklet yee Reply Link to post Share on other sites More sharing options...
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