Question 277: Atoms & Nuclei

Question

Two radioactive materials A and B have decay
constants 10$$\lambda $$ and $$\lambda $$, respectively. It initially
they have the same number of nuclei, then the
ratio of the number of nuclei of A to that of B
will be 1/e after a time :

Accepted Answer

N
1
= N
0
e
Ã¢ÂÂ10$$\lambda $$t
; N
2
= N
0
e
Ã¢ÂÂ$$\lambda $$t
$${1 \over e} = {{{N_1}} \over {{N_2}}} = {e^{ - 9\lambda t}}$$
$$ \Rightarrow 9\lambda t = 1$$
$$ \Rightarrow t = {1 \over {9\lambda }}$$

Answer

1/9$$\lambda $$

Answer

11/10$$\lambda $$

Answer

1/10$$\lambda $$

Answer

1/11$$\lambda $$

Atoms & Nuclei

Two radioactive materials A and B have decay constants 10$\lambda and \lambda $, respectively. It initially they have the same number of nuclei, then the ratio of the number of nuclei of A to that of B will be 1/e after a time :

Choose the correct answer: