Calculateur d'Énergie de Liaison par Nucléon
Calculez l'énergie de liaison par nucléon d'un noyau.
Activité
192,540,883,488.874 Bq
Activity vs Number of Radioactive Atoms (N)
Formule
Radioactive Activity
Activity is the rate of radioactive disintegrations per second. One Becquerel (Bq) equals one disintegration per second.
Formula
A = lambda × N = (ln2 / t½) × N
where lambda is the decay constant and N is the number of radioactive atoms. The older unit Curie: 1 Ci = 3.7 × 10¹⁰ Bq (the activity of 1 gram of Ra-226).
Exemple Résolu
10¹⁵ atoms of an isotope with half-life 3600 seconds (1 hour).
- 01lambda = ln(2) / 3600 = 1.925 × 10⁻⁴ s⁻¹
- 02A = 1.925 × 10⁻⁴ × 10¹⁵ = 1.925 × 10¹¹ Bq
- 03A = 1.925 × 10¹¹ / 3.7 × 10¹⁰ = 5.20 Ci
Questions Fréquentes
What is the practical difference between Bq and Ci?
Bq is the SI unit (1 disintegration/second). Ci is the traditional unit (3.7 × 10¹⁰ Bq). Medical doses are often in MBq or mCi. Environmental levels are in Bq/kg or pCi/L.
How many atoms are in 1 Ci of a substance?
N = A / lambda = 3.7 × 10¹⁰ × t½ / ln(2). For Tc-99m (t½ = 6h): N = 3.7 × 10¹⁰ × 21600 / 0.693 = 1.15 × 10¹⁵ atoms, which is about 0.2 nanograms.
Does specific activity depend on isotope?
Yes. Specific activity (Bq/g) = lambda × NA / M, where NA is Avogadro number and M is atomic mass. Short-lived isotopes have enormous specific activity. Carrier-free isotopes have the maximum specific activity.
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