The mean life of a radioactive sample are 30, | vedclass

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Question

$\mathrm{T}_{1 / 2}=\frac{0.693}{\lambda}=\frac{0.693}{\lambda_{1}+\lambda_{2}}=\frac{0.693}{\frac{1}{30}+\frac{1}{60}}$

${=\frac{0.693 	imes 30 \

Vedclass · Accepted Answer

$28$

Vedclass · Answer

$\mathrm{T}_{1 / 2}=\frac{0.693}{\lambda}=\frac{0.693}{\lambda_{1}+\lambda_{2}}=\frac{0.693}{\frac{1}{30}+\frac{1}{60}}$

${=\frac{0.693 	imes 30 	imes 60}{90} \approx 14 	ext { years }} $

For $\frac{1}{4} $ remains two half lives passed out 

${\Rightarrow \mathrm{t}=2 \mathrm{T}_{1 / 2}=28 \mathrm{\,years}}$

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