If half life of a radioactive element is 3, hours , after 9, hours its activity becomes

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13.Nuclei

easy

If half life of a radioactive element is $3\, hours$, after $9\, hours$ its activity becomes

A

$1/9$

B

$1/27$

C

$1/6$

D

$1/8$

Solution

(d) By using $A = {A_0}{\left( {\frac{1}{2}} \right)^{\frac{t}{{{T_{1/2}}}}}}$

==> $\frac{A}{{{A_0}}} = {\left( {\frac{1}{2}} \right)^{9/3}} = \frac{1}{8}$

Standard 12

Physics

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