The half-life of a radioactive substance is 2 seconds. Calculate the decay constant.

A.

2.890 s-1

B.

1.445 s-1

C.

0.576 s-1

D.

0.347s-1

E.

0.152 s-1

Correct answer is D

\(T_{\frac{1}{2}} = \frac{\ln 2}{\lambda}\)

where \(T_{\frac{1}{2}}\) = half-life of element; \(\lambda\) = decay constant.

= \(\frac{0.693}{\lambda}\)

\(\therefore 2 = \frac{0.693}{\lambda}\)

\(\lambda = \frac{0.693}{2}\)

= 0.3465 s\(^{-1}\)

\(\approxeq\) 0.347 s\(^{-1}\)