A radioactive sample S₁ has activity 5 μCi and contains twice as many nuclei as another sample S₂, whose activity is 10 μCi. Which pair can be the half-lives of S₁ and S₂?
Options

Question

A radioactive sample S₁ has activity 5 μCi and contains twice as many nuclei as another sample S₂, whose activity is 10 μCi. Which pair can be the half-lives of S₁ and S₂?

G1 Physics · Accepted Answer

Step 1: Use N(t) = N₀ exp(−λt), A = λN and T₁/₂ = ln2/λ. Step 2: For two samples, write the decay law separately and equate the required activities/numbers. Final: A: 20 years and 5 years, respectively.