Starting with a sample of pure {}^{66}Cu , 7/8 of it decays into Zn in 15 minutes . The&n

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13.Nuclei

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Starting with a sample of pure ${}^{66}Cu$, $7/8$ of it decays into $Zn$ in $15\ minutes$ . The it decays into $Zn$ in $15\ minutes$ . The corresponding half-life is ................ $minutes$

A

$15$

B

$5$

C

$7$

D

$3.75$

Solution

$\frac{N}{N_{o}}=\frac{1}{8}=\left(\frac{1}{2}\right)^{n}$

$n=3=\frac{t}{t_{1 / 2}}$

$\mathrm{t}_{1 / 2}=\mathrm{t} / 3=\frac{15}{3}=5 \mathrm{\,min}$

Standard 12

Physics

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