Question

If the radioactive decay constant of radium is $1.07\times {10}^{-4}peryear$. Then its half life period approximately is equal to

• A. $5000years$
• B. $6500years$
• C. $7000years$
• D. $8900years$

Answer 1

Answer: (B)

$6500years$

$\lambda =1.07\ast {10}^{-4}$

we know the half life formula:

$T_{0.5}=\frac{0.693}{\lambda }$

$T_{0.5}=\frac{0.693}{1.07\ast {10}^{-4}}$

$T_{0.5}=0.6477\ast {10}^4\approx 6500$ years.

Hence option 'B' is correct.