Question

If the decay constant of radioactive radium is $4.28\times {10}^{4}year{s}^{-1}$, this 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

As we know,
for first order reaction
$T_{1/2}=\frac{0.693}{\lambda }=\frac{0.693}{4.28\times {10}^{-4}}=1620years$