JAMB - Physics (2025 - No. 28)
Calculate the decay constant of a radioactive isotope of half-life 138.5 s.
5.0 × 10\(^{-3}\) s\(^{-1}\)
5.1 × 10\(^{-3}\) s\(^{-1}\)
4.9 × 10\(^{-3}\) s\(^{-1}\)
5.2 × 10\(^{-3}\) s\(^{-1}\)
설명
Answer: A
λ = \(\frac{ln2}{T½ }\) ⇒ \(\frac{0.693}{138.5}\) ≈ 5.0 × 10\(^{-3}\) s\(^{-1}\).