Half life period of radium is 1600 years. fraction of a sample of radium that would remain after 640

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13.Nuclei

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The half life period of radium is $1600$ years. The fraction of a sample of radium that would remain after $6400$ years is

A

$\frac{1}{4}$

B

$\frac{1}{2}$

C

$\frac{1}{8}$

D

$\frac{1}{{16}}$

(AIPMT-1991)

Solution

(d)Fraction $ = \frac{N}{{{N_0}}} = {\left( {\frac{1}{2}} \right)^{\frac{{6400}}{{1600}}}} = {\left( {\frac{1}{2}} \right)^4} = \frac{1}{{16}}$

Standard 12

Physics

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