(A) The activity of a radioactive sample reduces by half in one half-life $(T_{1/2} = 6 \,h)$.Let $s$ be the permissible safe value of the source.The

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(A) The activity of a radioactive sample reduces by half in one half-life $(T_{1/2} = 6 \,h)$.Let $s$ be the permissible safe value of the source.The initial activity is $32s$.After $1$ half-life, activity = $32s / 2 = 16s$.After $2$ half-lives, activity = $16s / 2 = 8s$.After $3$ half-lives, activity = $8s / 2 = 4s$.After $4$ half-lives, activity = $4s / 2 = 2s$.After $5$ half-lives, activity = $2s / 2 = s$.Thus, the sample becomes safe after $5$ half-lives.The total time $T = 5 \times T_{1/2} = 5 \times 6 \,h = 30 \,h$.

Class 12 Physics Nuclei Law of Radioactivity by Rutherford and Soddy and Half Life and Mean Life

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$A$ radioactive source has a half-life of $6 \,h$. $A$ freshly prepared sample of the same exhibits radioactivity $32$ times the permissible safe value. The minimum time after which it would be possible to work safely with the source is (in $\,h$)

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$30$
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$24$
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$18$
D
$12$

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Law of Radioactivity by Rutherford and Soddy and Half Life and Mean Life

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The half-life of a radioactive element which has only $\frac{1}{32}$ of its original mass left after a lapse of $60\, days$ is ........ $days$.

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$A$ radioactive material decays by simultaneous emissions of two particles with half-lives of $1400 \, years$ and $700 \, years$ respectively. What will be the time after which one-third of the material remains? (Take $\ln 3 = 1.1$) (In $years$)

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$A$ radioactive source has a half-life of $6 \,h$. $A$ freshly prepared sample of the same exhibits radioactivity $32$ times the permissible safe value. The minimum time after which it would be possible to work safely with the source is (in $\,h$)

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At any instant,the ratio of the amount of two radioactive substances is $2 : 1$. If their half-lives are $12$ hours and $16$ hours respectively,what will be the ratio of the substances after two days?

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