Scientific Units
Specialist units of physics, chemistry and radiation protection that remain in use alongside the SI. 7 units are listed.
| Unit | Symbol | Quantity | Value in SI |
|---|---|---|---|
| Electronvolt | eV | Energy | 1.602176634 × 10⁻¹⁹ J (exact) |
| Dalton | Da | Mass | 1/12 of a carbon-12 atom ≈ 1.66054 × 10⁻²⁷ kg |
| Barn | b | Area | 10⁻²⁸ m² (exact) |
| Thermochemical calorie | cal | Energy | 4.184 J (exact) |
| Ton of TNT | tTNT | Energy | 4.184 × 10⁹ J (exact by convention) |
| Curie | Ci | Radioactivity | 3.7 × 10¹⁰ Bq (exact) |
| Roentgen | R | Radiation exposure | 2.58 × 10⁻⁴ C/kg (exact) |