Question

The age of a vegetarian beverage whose tritium content is 15% of the level in the living plants is :
$(t_{1/2}for{}_1^3\text{H}=12.3year)$

• A. 33.68 year
• B. 35.65 year
• C. 43.80 year
• D. None of these

Answer 1

The correct option is A 33.68 year

Let the initial amount of tritium $N_0=100g$
Let the amount of tritium after time $t$ be $B=15g$
$k=\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{12.3}{yr}^{-1}$
$t=\frac{2.303}{k}\log \frac{N_0}{N}=\frac{2.303\times 12.3}{0.693}.\log \frac{100}{15}$
$=\frac{2.303\times 12.3\times 0.8239}{0.693}=33.68$ years