Question

Tritium, or hydrogen-3, is formed in the upper atmosphere by cosmic rays, similar to the formation of C-14. Tritium has been used to determine the age of wines. A certain wine that has been aged in a bottle has a tritium content only 78% of that in a similar wine of the same that has just been bottled. How long has the aged wine been in the bottle? $T_{50}$ of tritium is 12.2 years.
Plan Use $\lambda =\frac{2.303}{t}log\frac{N_0}{N}$ and $\lambda =\frac{0.693}{T_{50}}$
Thus, time t can be calculated.

• A. $4.375$ years
• B. $7.675$ years
• C. $6.475$ years
• D. None of these

Answer 1

The correct option is A $4.375$ years

$\lambda =\frac{2.303}{t}log\frac{N_0}{N}$
$\frac{0.693}{T_{50}}=\frac{2.303}{t}log\frac{N_0}{N}$
$\frac{0.693}{12.2}=\frac{2.303}{t}log\frac{100}{78}$
$\therefore$ $t=4.375$ years