Question

The radioisotope, tritium $(_{1}^{3} ⥂ H)$ has a half-life of 12.3 years. If the initial amount of tritium is 32 mg. How many milligrams of it would remain after 49.2 years

• A. 8 mg
• B. 1 mg
• C. 2 mg
• D. 4 mg

Answer 1

Answer: (C)

2 mg

Answer 2

$N_{t} = N_{o}\left( \frac{1}{2} \right)^{n} = 32 \times \left( \frac{1}{2} \right)^{49.2/12.3} = 32 \times \left( \frac{1}{2} \right)^{4} = 2$.