Activity (Becquerels) Calculator
Rate of radioactive decay.
Formula first
Overview
Radioactive activity represents the rate at which an unstable atomic nucleus undergoes spontaneous transformation by emitting radiation. It is measured in Becquerels, where one unit equals one nuclear disintegration per second.
Symbols
Variables
N = Total Decays, t = Time, A = Activity
Apply it well
When To Use
When to use: This formula is used to calculate the average rate of decay over a set period or to determine the total number of events in a sample. It is most accurate when the observation time is significantly shorter than the isotope's half-life, ensuring the decay rate remains relatively constant.
Why it matters: Quantifying activity is vital for medical diagnostics, where precise dosages of radiopharmaceuticals must be administered to patients. It also enables safety monitoring in nuclear power plants and assists in carbon dating for geological and archaeological research.
Avoid these traps
Common Mistakes
- Using total sample count instead of decay rate.
One free problem
Practice Problem
A radioactive sample is observed to undergo 5,400 nuclear disintegrations over the course of 3 minutes. Calculate the average activity of the source in Becquerels.
Solve for:
Hint: Convert the time from minutes to seconds before dividing the number of decays by the time duration.
The full worked solution stays in the interactive walkthrough.
References
Sources
- Wikipedia: Activity (radioactivity)
- IUPAC Gold Book: Activity (A00109)
- Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers (10th ed.). Cengage Learning.
- NIST Special Publication 811: Guide for the Use of the International System of Units (SI)
- IUPAC Gold Book: Becquerel
- Wikipedia: Becquerel
- Wikipedia: Curie
- Halliday, Resnick, Walker Fundamentals of Physics, 10th ed.