Question 519: Atoms & Nuclei

Question

Radioactive material 'A' has decay constant '8 $$\lambda $$' and material 'B' has decay constant '$$\lambda $$'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be e ?

Accepted Answer

Ratio of number of nuclei
$${{{N_1}} \over {{N_2}}} = {{{e^{ - 8\lambda t}}} \over {{e^{ - \lambda t}}}}$$ = $${{e^{ - 7\lambda t}}}$$
According to question,
$${{e^{ - 7\lambda t}}}$$ = $${1 \over e}$$
$$ \Rightarrow $$ t = $${1 \over {7\lambda }}$$

Answer

$${1 \over {7\lambda }}$$

Answer

$${1 \over {8\lambda }}$$

Answer

$${1 \over {9\lambda }}$$

Answer

$${1 \over {\lambda }}$$

Atoms & Nuclei

Radioactive material 'A' has decay constant '8 $\lambda ' and material 'B' has decay constant '\lambda $'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be e ?

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