Half-life of a radioactive substance is 3.6 days. How much of 20, mg of this radioactive substance w

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13.Nuclei

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The half-life of a radioactive substance is $3.6$ days. How much of $20\, mg$ of this radioactive substance will remain after $36$ days ............. $mg$

A

$0.0019$

B

$1.019$

C

$1.109$

D

$0.019$

Solution

(d) $M = {M_0}{\left( {\frac{1}{2}} \right)^{\frac{t}{{{T_{1/2}}}}}}$

$ = 20 \times {\left( {\frac{1}{2}} \right)^{\frac{{3.6}}{{3.6}}}}$

$ = 20 \times {\left( {\frac{1}{2}} \right)^{10}} = 0.019\,mg$

Standard 12

Physics

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