Activity of N nuclei with decay constant λ:
AA = e^N
BA = 1/N
CA = λ N (rate of decay = number remaining × decay constant)
DA = N/λ
Answer & Solution
Correct answer: C. A = λ N (rate of decay = number remaining × decay constant)
Activity A = -dN/dt = λN. Units: becquerel (Bq = 1 decay/sec) or curie (1 Ci = 3.7 × 10¹⁰ Bq). Decreases exponentially with same half-life as N.
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