activity definition

Question

Activity A of sample equals?

RankGuru · Accepted Answer

1. **Definition**: The activity ($A$) of a radioactive sample is the number of disintegrations occurring per unit time.
2. **Mathematical Relation**: $A = -\frac{dN}{dt}$.
3. **Relationship to Decay Constant**: Since rate of decay is proportional to identity of nuclei present ($\frac{dN}{dt} = -\lambda N$):
   - $A = \lambda N$
4. **Units**: The SI unit of activity is the **Becquerel (Bq)**, defined as one disintegration per second. Another unit is the **Curie (Ci)**.

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activity definition

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