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
Verified Correct Answer: E.
Physical Principles & Numerical Solution
\(\frac{N}{3}\) = 3years
\(\frac{N}{4}\) = 6years
\(\frac{N}{8}\) = 9years
N - \(\frac{N}{8}\) = \(\frac{7N}{8}\)
Source: Myschool Past Questions Archive (Record #24297)