Nuclear Physics And Radioactivity Question 496

Question: 99% of a radioactive element will decay between

Options:

A) 6 and 7 half lives

B) 7 and 8 half lives

C) 8 and 9 half lives

D) 9 half lives

Show Answer

Answer:

Correct Answer: A

Solution:

[a] $ N=N_{0}{{( \frac{1}{2} )}^{n}}\Rightarrow \frac{N}{N_{0}}={{( \frac{1}{2} )}^{n}} $
$ \Rightarrow \frac{1}{100}={{( \frac{1}{2} )}^{n}}\Rightarrow 2^{n}=100 $ n comes out in between 6 and 7.