Question

Radioactive decay follows first order kinetics and the rate constant is often termed as decay constant. Certain radioactive substances may undero sequential decays in order to convert into a stable nucleus. The series comprising all such elements is termed as radioactive disintegration series.
A radioactive series is formed such that after each ` alpha` decay there are two consecutive `beta` decay and the cycle repeats. How many different elements this series can have if there are 12 members in the series ?
A. 12
B. 4
C. 3
D. 6

Answer 1

Correct Answer - C
After a very long time `: lambda_(1)N_(A)=lambda_(2)N_(B)`
`(N_(A))/(N_(B))=(lambda_(1))/(lambda_(2))=(4 xx 10^(-2))/(16 xx10^(-5))=(1)/(4)=10^(-7)=2.5 xx 10^(-8) `