Radon ({Rₙ}) decays into Polonium ( {P_0} ) by emitting an α - particle with half-life of 4, days

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13.Nuclei

easy

Radon $({R_n})$ decays into Polonium (${P_0}$) by emitting an $\alpha - $ particle with half-life of $4\, days$. A sample contains $6.4 \times {10^{10}}$ atoms of $R_n$. After $12\, days$, the number of atoms of ${R_n}$ left in the sample will be

A

$3.2 \times {10^{10}}$

B

$0.53 \times {10^{10}}$

C

$2.1 \times {10^{10}}$

D

$0.8 \times {10^{10}}$

Solution

(d) In the given case, $12\, days = 3 $ half lives Number of atoms left after $3$ half lives.

$ = 6.4 \times {10^{10}} \times \frac{1}{{{2^3}}} = 0.8 \times {10^{10}}$

Standard 12

Physics

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