Question Detail
Question
Counting rate 8000 counts/s at t=0, 1000 counts/s after 10 minutes. Decay constant?
Correct Answer
Option C is the correct answer.
Detailed Explanation
A = A₀ e^{-λt} → 1000 = 8000 e^{-λ×10} → e^{-10λ} = 1/8 → -10λ = ln(1/8) = -2.079 → λ = 0.2079 min⁻¹.
Hint
λ = ln(A₀/A)/t.