Question 208: Atoms & Nuclei

Question

Two radioactive substances X and Y originally have N
1
and N
2
nuclei respectively. Half life of X is half of the half life of Y. After three half lives of Y, number of nuclei of both are equal. The ratio $${{{N_1}} \over {{N_2}}}$$ will be equal to :

Accepted Answer

Let Half life of x = t
then half life of y = 2t
when 3 half life of y is completed then 6 half life of x is completed.
$$ 	herefore $$ Now x have = $${{{N_1}} \over {{2^6}}}$$ nuclei
and y have = $${{{N_2}} \over {{2^3}}}$$ nuclei
From question,
$${{{N_1}} \over {{2^6}}} = {{{N_2}} \over {{2^3}}}$$
$$ \Rightarrow {{{N_1}} \over {{N_2}}} = 8$$

Answer

$${1 \over 8}$$

Answer

$${3 \over 1}$$

Answer

$${1 \over 3}$$

Answer

$${8 \over 1}$$

Atoms & Nuclei

Two radioactive substances X and Y originally have N 1 and N 2 nuclei respectively. Half life of X is half of the half life of Y. After three half lives of Y, number of nuclei of both are equal. The ratio ${{{N_1}} \over {{N_2}}}$ will be equal to :

Choose the correct answer: