Question

They decay constant of radium is $4.28\times 10^{-4}$ per year. Its half life will be

• A. 2000 years
• B. 1240 years
• C. 63 years
• D. 1620 years

Answer 1

Answer: (D)

$T=\frac{0.6931\times 1}{\lambda }=\frac{0.6931}{4.28\times 10^{-4}}$ year $=1620$ years