Nucleus: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Nucleus. Understanding the underlying formula is key to arriving at the correct answer below:

Activity $A = \lambda N = \frac{\ln 2}{T_{1/2}} N$. Substituting the values gives $A \approx \frac{0.693}{1.4 \times 10^{17}} \times 2.0 \times 10^{21} \approx 0.99 \times 10^4 Bq$, which is nearly $10^4 Bq$.