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Radioactive decay follows exponential decay law. The decay rate depends on the decay constant and the number of remaining nuclei.
Fórmula
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)
Guia passo a passo
- 1Enter initial activity or mass, decay constant (or half-life), and elapsed time
- 2The calculator applies N(t) = N₀ × e^(-λt) or A(t) = A₀ × e^(-λt)
- 3Results show remaining nuclei or activity
Exemplos resolvidos
Entrada
N₀ = 1 mol (6.022 × 10²³), λ = 0.693/5730 yr⁻¹ (¹⁴C), t = 5730 yr
Resultado
N ≈ 0.5 mol (50%)
One half-life
Erros comuns a evitar
- ✕Using decay constant instead of half-life without converting
- ✕Assuming linear decay instead of exponential
Perguntas frequentes
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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