A radioactive isotope has half-life 693 s. Use ln2 = 0.693. If the mean life is N seconds, find N.

Question

G1 Physics · Accepted Answer

The relations are T₁⁄₂ = ln2 ÷ λ and τ = 1 ÷ λ. Therefore, τ = T₁⁄₂ ÷ ln2. Substitute: τ = 693 ÷ 0.693 = 1000 s. Hence N = 1000.