Radioactive Decay & Half-Life Calculator
Calculate exponential radioactive decay N(t) = N₀(½)^(t/t½), remaining percentage, isotope decay constants, and C-14 radiocarbon dating.
Calculated Results
Frequently Asked Questions
What is the radioactive decay half-life formula?
The exponential decay formula is: N(t) = N₀ × (½)^(t / t½), or N(t) = N₀ × e^(-λt), where N₀ is initial quantity, t is elapsed time, t½ is half-life, and λ = ln(2) / t½ is the decay constant.
What is the '10 half-life rule' in nuclear physics?
As a rule of thumb in nuclear waste management and radiation safety, an isotope is considered decayed to negligible background levels after 10 half-lives (at which point (½)¹⁰ = 0.098% or less than one-thousandth of original activity remains).
How does Carbon-14 radiocarbon dating work?
Living organisms absorb atmospheric Carbon-14 throughout life. Upon death, Carbon-14 stops replenishing and decays with a half-life of 5,730 years into Nitrogen-14. By measuring the ratio of remaining C-14 to stable C-12, archaeologists date organic artifacts up to ~50,000 years old.
What is the difference between Becquerels and Curies?
A Becquerel (Bq) is the SI unit equal to 1 radioactive decay per second. A Curie (Ci) is the traditional unit based on 1 gram of Radium-226, equal to 37 billion decays per second (3.7 × 10¹⁰ Bq).