Question

The half life of a radioactive substance is \(13\) years. The decay constant is,

Answer 1

Half life period, \(T_{1/2} = 13~\text{years}\)
\(T=13 \times 365\times 86400~\text{sec}\)
Decay constant is given by,
\(\lambda = \dfrac{0.693}{T_{1/2}}\)

=\(\dfrac{693 \times10^{-3}}{13 \times365 \times 86400}\)

\(\lambda=1.69 \times10^{-9}~ \text{sec}^{-1}\)

Hence, \((C)\) is the correct answer.