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
Verified Correct Answer: D.
Physical Principles & Numerical Solution
\(T_{\frac{1}{2}} = \frac{\ln 2}{\lambda}\)
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\(^{-1}\)
Source: Myschool Past Questions Archive (Record #42685)