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Radioactive decay follows exponential decay law. The decay rate depends on the decay constant and the number of remaining nuclei.

Формула

The calculator applies N(t) = N₀ × e^(-λt) or A(t) = A₀ × e^(-λt)
N
N₀ × e^(-λt) or A(t) = A₀ × e^(-λt) — N₀ × e^(-λt) or A(t) = A₀ × e^(-λt)
A
A₀ × e^(-λt) — A₀ × e^(-λt)

Водич корак по корак

  1. 1Enter initial activity or mass, decay constant (or half-life), and elapsed time
  2. 2The calculator applies N(t) = N₀ × e^(-λt) or A(t) = A₀ × e^(-λt)
  3. 3Results show remaining nuclei or activity

Worked Examples

Инпут
N₀ = 1 mol (6.022 × 10²³), λ = 0.693/5730 yr⁻¹ (¹⁴C), t = 5730 yr
Резултат
N ≈ 0.5 mol (50%)
One half-life

Common Mistakes to Avoid

  • Using decay constant instead of half-life without converting
  • Assuming linear decay instead of exponential

Frequently Asked Questions

Can radioactivity be accelerated or stopped?

No, decay rate is determined by nuclear physics and cannot be changed by temperature, pressure, or chemistry.

What's the difference between activity and amount?

Amount is number of nuclei (decreasing exponentially); activity is decay rate (also decreasing, at same rate).

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