Activity of a radioactive sample is 1.6, curie and its half-life is 2.5 ,days . Its activity after 1

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13.Nuclei

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The activity of a radioactive sample is $1.6\, curie$ and its half-life is $2.5 \,days$. Its activity after $10\, days$ will be .......... $curie$

A

$0.8 $

B

$0.4$

C

$0.1$

D

$0.16$

Solution

(c) Number of half lives $n = \frac{{10}}{{2.5}} = 4$

==> $\frac{A}{{{A_0}}} = \frac{N}{{{N_0}}} = {\left( {\frac{1}{2}} \right)^n} $

$\Rightarrow A = 1.6 \times {\left( {\frac{1}{2}} \right)^4} = 0.1\;curie$

Standard 12

Physics

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