Question

If the decay constant of radium is $4.28\times {10}^{-4}$ per year, then its half life will be approximately be

• A. $1240$ years
• B. $1620$ years
• C. $2000$ years
• D. $2260$ years

Answer 1

Answer: (B)

$1620$ years

Decay constant. $\lambda =4.28\times {10}^{-4}$

Half life, $t_{1/2}={\log }_{e}2/\lambda =0.693/4.28\times {10}^{-4}\approx 1620years$