Question

The 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

The correct option is D $1620$ years

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