Radioactive Decay Calculator
Calculate activity, specific activity, and half-life for radioactive materials
Calculate Radioactive Decay
Mass of the radioactive sample in grams
Molar mass of the isotope in g/mol
Half-life of the radioactive isotope
Radioactive Decay Results
Activity Formula: A = λN = (N_A × m × ln(2)) / (M × t₁/₂)
Decay Constant: λ = ln(2) / t₁/₂ = 4.914e-9 s⁻¹
Safety Assessment: Extreme caution and shielding required
Applications: Nuclear power, research reactors
Time Scale: Years to centuries
Example Calculations
Banana Radioactivity
Natural K-40 in a banana
Expected: ~15 Bq
Carbon Dating Sample
Archaeological carbon sample
Expected: ~0.2 Bq/g
Medical Iodine Tracer
Thyroid imaging dose
Expected: ~400 MBq
Plutonium Core (Fat Man)
Historical nuclear weapon core
Expected: ~14 TBq
Activity Level Guide
< 1 Bq
Very low activity
Background radiation level
1 - 1,000 Bq
Low activity
Educational sources
1 kBq - 1 MBq
Moderate activity
Medical tracers
1 MBq - 1 GBq
High activity
Industrial sources
> 1 GBq
Very high activity
Nuclear materials
Activity Units
Types of Radioactive Decay
Understanding Radioactive Decay
What is Radioactive Decay?
Radioactive decay is a random process where unstable atomic nuclei spontaneously transform into more stable configurations by emitting radiation. This process follows predictable statistical patterns described by exponential decay laws.
Key Concepts
- •Activity (A): Number of decays per second (Becquerels)
- •Half-life (t₁/₂): Time for half the nuclei to decay
- •Decay constant (λ): Probability of decay per unit time
- •Specific activity: Activity per unit mass (Bq/kg)
Radioactive Decay Formulas
Activity Formula
A = λN = (N_A × m × ln(2)) / (M × t₁/₂)
Where N_A is Avogadro's number
Decay Constant
λ = ln(2) / t₁/₂
Relates half-life to decay probability
Specific Activity
a = (N_A × ln(2)) / (M × t₁/₂)
Activity per unit mass
Applications and Safety
Medical Applications
Nuclear medicine uses radioactive tracers for imaging and therapy, with carefully calculated activities for safety.
Dating Methods
Carbon-14 dating and other radiometric techniques use decay rates to determine ages of materials.
Nuclear Power
Understanding decay rates is crucial for reactor operation, waste management, and radiation safety.