The activity of radioactive sample is measured as N ₀ counts per minute at time t = o , and N ₀ e counts per minute at time t =3 minute, The activity reduces to half its value in time (in minute)

Step-by-step solution

The activity follows radioactive decay: A = A₀ e^ - t . Given A = N₀ e when t = 3 minutes, substitution yields: N₀ e = N₀ e^ -3 Simplification gives e⁻¹ = e^ -3 , from which = 1 3 per minute. The half-life is T_ 1/2 = 2 = 3 2 minutes, matching option B. Final Answer: B