Posted by TITA on Monday, November 23, 2009 at 7:19pm.
If a sample of a radioactive isotope has a halflife of 5 year(s), how much of the original sample will be left at the end of the second year?
How much will be left at the end of the third year of thr original sample?
How much will be left at the end of the fourth year of the original sample?

Physics  drwls, Monday, November 23, 2009 at 7:45pm
Fraction left at t = (1/2)^(t/T)
where T is the half life, which is 5 years in this case.
For the first question, solve
(1/2)^(2/5) = 75.8%
Repeat using the same formula for the other times t.