An element whose half-life is 3 years has N atoms. How many atoms would have decayed after 9 years
-
A.
1 N atoms8 -
B.
1 N atoms3 -
C.
2 N atoms3 -
D.
5 N atoms6 -
E.
7 N atoms8
Correct Answer: Option E
Explanation
(frac{N}{3}) = 3years
(frac{N}{4}) = 6years
(frac{N}{8}) = 9years
N – (frac{N}{8}) = (frac{7N}{8})