A radioactive element undergoes two different types of radioactive disintegration, one with disintegration constant λ1 and the other with λ2. The half-life of the element is
Answer & explanation
Correct answer: option 1
Let equivalent decay constant is $\lambda$
$ \lambda N = \lambda_1 N + \lambda_2 N$
$ \Rightarrow \lambda = \lambda_1 + \lambda_2$
$ \tau = \frac{0.693}{\lambda}= \frac{0.693}{\lambda_1 + \lambda_2}$