To determine the age of a stone it was analysed for the nuclei of 'B' & 'D' and were found to be 1018 and 3 × 1018 respectively. Assuming that all the 'D' was produced by the disintegration of 'A' only, the age of the stone is [Given : ℓn 2 = 0.3, ℓn 3 = 0.45]

Engineering

Chemistry

Kinetics of Radioactive Decay

Question

To determine the age of a stone it was analysed for the nuclei of 'B' & 'D' and were found to be 10¹⁸ and 3 × 10¹⁸ respectively. Assuming that all the 'D' was produced by the disintegration of 'A' only, the age of the stone is

[Given : ℓn 2 = 0.3, ℓn 3 = 0.45]

3465 days

10395 days

6930 days

13860 days

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$t = \frac{6930}{\ln 2} \ln \frac{{[B]}_{initial}}{{[B]}_{final}}$

$= \frac{6930}{\ln 2} \ln \frac{4 \times 10^{18}}{1 \times 10^{18}} = 13860 days$