Question

The decay constant of radium is $4.28 \times 10^{-4}$ per yr .Its half-life is approximately

• A. 1250 yr
• B. 1620 yr
• C. 200 yr
• D. 60 yr

Answer 1

Answer: (B)

1620 yr

Answer 2

Half-life $T_{1/2} = \frac{0.693}{\lambda}$ $= \frac{0.693}{4.28 \times 10^{-4} } \approx 1620 yr$