| # t½ | Time | Remaining | % |
|---|---|---|---|
| 0 | 0 | 100 | 100% |
| 1 | 10 | 50 | 50% |
| 2 | 20 | 25 | 25% |
| 3 | 30 | 12.5 | 12.5% |
| 4 | 40 | 6.25 | 6.25% |
| 5 | 50 | 3.125 | 3.125% |
| 7 | 70 | 0.78125 | 0.78125% |
| 10 | 100 | 0.097656 | 0.097656% |
Any quantity that decays exponentially — radioactive isotopes, drug concentration, capacitor voltage — obeys N(t) = N₀ · (1/2)^(t/t½). The half-life t½ is the time for the quantity to halve.
Decay constant λ = ln(2)/t½ links half-life to the alternative formulation N(t) = N₀ · e^(−λt). Mean lifetime τ = 1/λ ≈ 1.44 · t½.
Any quantity that decays exponentially — radioactive isotopes, drug concentration, capacitor voltage — obeys N(t) = N₀ · (1/2)^(t/t½). The half-life t½ is the time for the quantity to halve.
Decay constant λ = ln(2)/t½ links half-life to the alternative formulation N(t) = N₀ · e^(−λt). Mean lifetime τ = 1/λ ≈ 1.44 · t½.
| # t½ | Time | Remaining | % |
|---|---|---|---|
| 0 | 0 | 100 | 100% |
| 1 | 10 | 50 | 50% |
| 2 | 20 | 25 | 25% |
| 3 | 30 | 12.5 | 12.5% |
| 4 | 40 | 6.25 | 6.25% |
| 5 | 50 | 3.125 | 3.125% |
| 7 | 70 | 0.78125 | 0.78125% |
| 10 | 100 | 0.097656 | 0.097656% |