Calculate the decay constant of a radioactive isotope of half-life 138.5 s.
A
5.0 × 10\(^{-3}\) s\(^{-1}\)
B
5.1 × 10\(^{-3}\) s\(^{-1}\)
C
4.9 × 10\(^{-3}\) s\(^{-1}\)
D
5.2 × 10\(^{-3}\) s\(^{-1}\)
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Answer: A
λ = \(\frac{ln2}{T½ }\) ⇒ \(\frac{0.693}{138.5}\) ≈ 5.0 × 10\(^{-3}\) s\(^{-1}\).
Source: WAEC / JAMB / NECO Classroom Archive (Record #74374)