(A) The number of half-lives $(n)$ is calculated as $n = \frac{\text{Total time}}{\text{Half-life}} = \frac{40 \ days}{20 \ days} = 2$. The amount of

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(A) The number of half-lives $(n)$ is calculated as $n = \frac{\text{Total time}}{\text{Half-life}} = \frac{40 \ days}{20 \ days} = 2$. The amount of substance remaining $(N)$ is given by the formula $N = \frac{N_0}{2^n}$,where $N_0$ is the initial amount. Substituting the values,$N = \frac{100 \ g}{2^2} = \frac{100}{4} = 25 \ g$.

Class 12 Chemistry Nuclear Chemistry Rate of decay and Half-life

Medium

$A$ radioactive isotope has a half-life of $20 \ days$. If $100 \ g$ of the substance is taken,the weight of the isotope remaining after $40 \ days$ is ......... $g$.

A
$25$
B
$2.5$
C
$60$
D
$40$

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Nuclear Chemistry

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Rate of decay and Half-life

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$A$ radioactive isotope has a half-life of $20 \ days$. If $100 \ g$ of the substance is taken,the weight of the isotope remaining after $40 \ days$ is ......... $g$.

Similar Questions

The $t_{1/2}$ of a radioactive element is $20 \ min$. The time interval between the stages of its $33\%$ and $67\%$ decay is ....... $min$.

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