Radioactive decay: _{An isotope of Tc having a half-life of 6.0 h is used in bone scans. If a certain amount of this Tc is injected into the body, how long does it take for its initial decay rate to decrease BY 99%?}

Question

Quizplus · Accepted Answer

The decay rate decreases by 99% when only 1% of the original remains. This corresponds to 6.64 half-lives (since 0.5^6.64 ≈ 0.01). Therefore, 6.64 half-lives of 6 hours each is approximately 40 hours.

Radioactive Decay: An Isotope of Tc Having a Half-Life of 6.0

Radioactive Decay: _{An Isotope of Tc Having a Half-Life of 6.0}