In radioactive decay of an element it is found that count rate reduces from 1024 to 128 in 3 minutes

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13.Nuclei

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In the radioactive decay of an element it is found that the count rate reduces from 1024 to $128$ in $3$ minutes. Its half life will be ...... minute

A

$1$

B

$2$

C

$3$

D

$5$

Solution

(a)

$\frac{R}{R_0}=\frac{128}{1024}$

$\frac{R}{R_0}=\frac{1}{8}$

$\text { or } \quad \frac{R}{R_0}=\left(\frac{1}{2}\right)^3$

$\therefore n=3$

$3$ half lives in $3$ minutes, $1$ half life in $1$ minute

Standard 12

Physics

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